Note: I cannot check the mail server logs because I am using Office365. I have confirmed through my web UI the port number for SMTP, authenticates with STARTTLS..

Results from https://www.checktls.com

seconds test stage and result
[000.008] Connected to server
[000.015] <-- 220 BL0PR02CA0071.outlook.office365.com Microsoft ESMTP MAIL Service ready at Tue, 30 Jul 2019 20:23:12 +0000
[000.015] We are allowed to connect
[000.015] --> EHLO www6.CheckTLS.com
[000.023] <-- 250-BL0PR02CA0071.outlook.office365.com Hello [159.89.187.50]
250-SIZE 157286400
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250 SMTPUTF8
[000.023] We can use this server
[000.023] TLS is an option on this server
[000.023] --> STARTTLS
[000.031] <-- 220 2.0.0 SMTP server ready
[000.031] STARTTLS command works on this server
[000.059] Connection converted to SSL
SSLVersion in use: TLSv1_2
Cipher in use: ECDHE-RSA-AES256-GCM-SHA384
Certificate 1 of 3 in chain: Cert VALIDATED: ok
Cert Hostname VERIFIED (smtp.office365.com = outlook.com | DNS:.clo.footprintdns.com | DNS:.nrb.footprintdns.com | DNS:.hotmail.com | DNS:.internal.outlook.com | DNS:.live.com | DNS:.office.com | DNS:.office365.com | DNS:.outlook.com | DNS:.outlook.office365.com | DNS:attachment.outlook.live.net | DNS:attachment.outlook.office.net | DNS:attachment.outlook.officeppe.net | DNS:ccs.login.microsoftonline.com | DNS:ccs-sdf.login.microsoftonline.com | DNS:hotmail.com | DNS:mail.services.live.com | DNS:office365.com | DNS:outlook.com | DNS:outlook.office.com | DNS:substrate.office.com | DNS:substrate-sdf.office.com | DNS:attachments.office.net | DNS:.fp.measure.office.com | DNS:attachments-sdf.office.net | DNS:outlook-sdf.graph.microsoft.com)
Not Valid Before: Jan 23 00:00:00 2019 GMT
Not Valid After: Jan 23 12:00:00 2021 GMT
subject= /C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=outlook.com
issuer= /C=US/O=DigiCert Inc/CN=DigiCert Cloud Services CA-1
Certificate 2 of 3 in chain: Cert VALIDATED: ok
Not Valid Before: Aug 4 12:00:00 2015 GMT
Not Valid After: Aug 4 12:00:00 2030 GMT
subject= /C=US/O=DigiCert Inc/CN=DigiCert Cloud Services CA-1
issuer= /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA
Certificate 3 of 3 in chain: Cert VALIDATED: ok
Not Valid Before: Nov 10 00:00:00 2006 GMT
Not Valid After: Nov 10 00:00:00 2031 GMT
subject= /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA
issuer= /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA
[000.139] > EHLO www6.CheckTLS.com
[000.148] < 250-BL0PR02CA0071.outlook.office365.com Hello [159.89.187.50]
250-SIZE 157286400
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-AUTH LOGIN XOAUTH2
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250 SMTPUTF8
[000.148] TLS successfully started on this server

4 months later

I've yet to succeed in setting up SMTP..

Office.com shows the following settings should work:

Server name: smtp.office365.com
Port: 587
Encryption method: STARTTLS

output from running "php -i" (only lines related to ssl):

Registered Stream Socket Transports => tcp, udp, ssl, tls, tlsv1.0, tlsv1.1, tlsv1.2
curl
SSL => Yes
MULTI_SSL => No
SSL Version => OpenSSL/1.1.1c
imap
SSL Support => enabled
mysqlnd
core SSL => supported
extended SSL => not supported
openssl
OpenSSL support => enabled
OpenSSL Library Version => OpenSSL 1.1.1c  28 May 2019
OpenSSL Header Version => OpenSSL 1.1.1c  28 May 2019
Openssl default config => C:\usr\local\ssl/openssl.cnf
Directive => Local Value => Master Value
openssl.cafile => no value => no value
openssl.capath => no value => no value
pgsql
SSL support => enabled
Phar
OpenSSL support => enabled

Different error displayed through osTicket after adding tls:// to smtp host

Sending Email via SMTP     
Failed to connect to tls://smtp.office365.com:587 [SMTP: Failed to connect socket: stream_socket_client(): unable to connect to tls://smtp.office365.com:587 (Unknown error) (code: -1, response: )]

from "php_errors.log":

PHP Warning:  stream_socket_client(): SSL operation failed with code 1. OpenSSL Error messages:
error:1408F10B:SSL routines:ssl3_get_record:wrong version number in C:\inetpub\wwwroot\osticket\include\pear\Net\Socket.php on line 166
PHP Warning:  stream_socket_client(): Failed to enable crypto in C:\inetpub\wwwroot\osticket\include\pear\Net\Socket.php on line 166
PHP Warning:  stream_socket_client(): unable to connect to tls://smtp.office365.com:587 (Unknown error) in C:\inetpub\wwwroot\osticket\include\pear\Net\Socket.php on line 166

osticket\include\pear\Net\Socket.php lines 148-171

        if ($options && function_exists('stream_context_create')) {
            if ($this->timeout) {
                $timeout = $this->timeout;
            } else {
                $timeout = 0;
            }
            $context = stream_context_create($options);

            // Since PHP 5 fsockopen doesn't allow context specification
            if (function_exists('stream_socket_client')) {
                $flags = STREAM_CLIENT_CONNECT;

                if ($this->persistent) {
                    $flags = STREAM_CLIENT_PERSISTENT;
                }

                $addr = $this->addr . ':' . $this->port;
                $fp   = stream_socket_client($addr, $errno, $errstr,
                                             $timeout, $flags, $context); // <--- Line 166
            } else {
                $fp = @$openfunc($this->addr, $this->port, $errno,
                                 $errstr, $timeout, $context);
            }
        } else {

So I've been connecting to o365 with osTicket since 1.10 just fine. I've also used PHP 5.6, 7.0.x, and 7.2.x

Here are the settings I use:

My primary site is currently running 1.14.1 under IIS 8.5 and my PHP version is 7.3.12.

I say this because I'm not sure why you are having an issue with it. Please try matching my settings and see what happens.

Thanks for the response!

latest osTicket info from /scp/system.php

Server Information
osTicket Version	v1.12.2 (a5d898b) — v1.12.5 is available
Web Server Software	Microsoft-IIS/10.0
MySQL Version	8.0.17
PHP Version	7.3.7


I don't have [_] Use Separate Authentication. ?

packet dump via WireShark:

packetNumber,time,source,destination,protocol,length,Info
"114","9.996556",osTicketServer,mailServer,"SMTP","70","C: EHLO localhost"
"115","10.025890",mailServer,osTicketServer,"SMTP","165","[TCP Spurious Retransmission] S: 220 SN1PR12CA0109.outlook.office365.com Microsoft ESMTP MAIL Service ready at Fri, 13 Dec 2019 15:16:32 +0000"
"116","10.025935",osTicketServer,mailServer,"TCP","66","[TCP Dup ACK 114#1] 50615 → 587 [ACK] Seq=17 Ack=112 Win=262656 Len=0 SLE=1 SRE=112"
"117","10.026672",mailServer,osTicketServer,"SMTP","258","S: 250-SN1PR12CA0109.outlook.office365.com Hello [XXX.XXX.XXX.XXX] | 250-SIZE 157286400 | 250-PIPELINING | 250-DSN | 250-ENHANCEDSTATUSCODES | 250-STARTTLS | 250-8BITMIME | 250-BINARYMIME | 250-CHUNKING | 250 SMTPUTF8"
"118","10.027100",osTicketServer,mailServer,"SMTP","64","C: STARTTLS"
"119","10.058055",mailServer,osTicketServer,"SMTP","258","[TCP Spurious Retransmission] S: 250-SN1PR12CA0109.outlook.office365.com Hello [XXX.XXX.XXX.XXX] | 250-SIZE 157286400 | 250-PIPELINING | 250-DSN | 250-ENHANCEDSTATUSCODES | 250-STARTTLS | 250-8BITMIME | 250-BINARYMIME | 250-CHUNKING | 250 SMTPUTF8"
"120","10.058084",osTicketServer,mailServer,"TCP","66","[TCP Dup ACK 118#1] 50615 → 587 [ACK] Seq=27 Ack=316 Win=262400 Len=0 SLE=112 SRE=316"
"121","10.058702",mailServer,osTicketServer,"SMTP","83","S: 220 2.0.0 SMTP server ready"
"122","10.059973",osTicketServer,mailServer,"SMTP","571","C: \026\003\001\002\000\001\000\001\374\003\003(H\003b | 9B\274\217\2433\273\002D\305\227\301 \016\274\347\343\260.\241\025a\275\216\265&J\000\000\220\300/\300+\3000\300,\000\236\000\242\000\243\000\237\300'\300#\300\023\300\t\300(\300$\300\024\300 | \000g\0003\000@\000k\0008\0009\000\234\000\235\300\256\300\254\300\242\300\236\0002\300\240\300\234\000<\000/\300\257\300\255\300\243\300\237\000j\300\241\300\235\000=\0005\314\251\314\250\314\252\300]\300a\300W\300S\300\\300`\300V\300R\300s\300w\000\304\000\303\300r\300v\000\276\000\275\000\210\000\207\000E\000D\300Q\300P\000\300\000\272\000\204\000A\000\377\001\000\001C\000\000\000\021\000\017\000\000\f40.97.212.18\000\v\000\004\003\000\001\002\000 | \000\f\000 | \000\035\000\027\000\036\000\031\000\030\000#\000\000\000\026\000\000\000\027\000\000\000 | \0000\000.\004\003\005\003\006\003\b\a\b\b\b\t\b | \b\v\b\004\b\005\b\006\004\001\005\001\006\001\003\003\002\003\003\001\002\001\003\002\002\002\004\002\005\002\006\002\000\025\000\322\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"
"123","10.084661",mailServer,osTicketServer,"SMTP","1514","S:  |  |  |  |  |  | 190123000000Z\027 | 210123120000Z0j1\v0\t\006\003U\004\006\023\002US1\0230\021\006\003U\004\b\023 |  |  |  |  |  |  |  |  |  |  |  | "
"124","10.126130",osTicketServer,mailServer,"TCP","54","50615 → 587 [ACK] Seq=544 Ack=1805 Win=262656 Len=0"
"125","10.131010",mailServer,osTicketServer,"SMTP","1514","[TCP Spurious Retransmission] S:  |  |  |  |  |  | 190123000000Z\027 | 210123120000Z0j1\v0\t\006\003U\004\006\023\002US1\0230\021\006\003U\004\b\023 |  |  |  |  |  |  |  |  |  |  |  | "
"126","10.131072",osTicketServer,mailServer,"TCP","66","[TCP Dup ACK 124#1] 50615 → 587 [ACK] Seq=544 Ack=1805 Win=262656 Len=0 SLE=345 SRE=1805"
"127","10.145610",mailServer,osTicketServer,"SMTP","1514","S:  |  |  |  |  |  |  |  |  |  |  | 150804120000Z\027 | 300804120000Z0K1\v0\t\006\003U\004\006\023\002US1\0250\023\006\003U\004 |  |  |  | "
"128","10.145970",mailServer,osTicketServer,"SMTP","1069","S:  |  |  |  |  |  | "
"129","10.146041",osTicketServer,mailServer,"TCP","54","50615 → 587 [ACK] Seq=544 Ack=4280 Win=262656 Len=0"
"130","10.255198",osTicketServer,mailServer,"TCP","61","50615 → 587 [PSH, ACK] Seq=544 Ack=4280 Win=262656 Len=7 [TCP segment of a reassembled PDU]"
"131","10.285520",mailServer,osTicketServer,"TCP","60","587 → 50615 [FIN, ACK] Seq=4280 Ack=551 Win=1048560 Len=0"
"132","10.285566",osTicketServer,mailServer,"SMTP","60","C: \025\003\003\000\002\002.RSET"
"133","10.315526",mailServer,osTicketServer,"TCP","60","587 → 50615 [RST, ACK] Seq=4281 Ack=557 Win=155216 Len=0"

I've asked a dev to take a look at this thread.

Thank you. I temporarily tried changing host:port
C:\php\php.ini:1027-1029,
osticket\include\pear\Mail\smtp.php:95-101,
osticket\include\pear\Mail\smtpmx.php:76-85
from localhost:25 to smtp.office.com:587,
I restarted IIS, and I still get EHLO localhost in wireshark when trying to set SMTP settings, so I reverted these latest changes..

    @emoreno

    I see that you receive the error routines:ssl3_get_record:wrong version number which could be an issue with OpenSSL installed on your server, etc. I'm not too familiar with this error so some googling will give you more information and possibly provide (or point) to a resolution.

    Cheers.

    emoreno
    not sure if this is typo or just missed: from localhost:25 to smtp.office.com:587 should be from localhost:25 to smtp.office365.com:587

      4 months later

      Hello, has anyone found a solution to this problem?I can get it to work at all.

      Web hosting at Bluehost and using Office365 for emails for many years working without a problem.
      Recently I installed osTicket which is amazing (thanks developers), but I can't get it to play nice with Office365. I thought given how popular Office365 is, it would be fairly straightforward. I've searched everywhere with no luck, unless I missed something late one night. I hope someone can help.

      Server Information
      osTicket Version v1.14.1 (f1e9e88) — Up to date
      Web Server Software Apache
      MySQL Version 5.6.41
      PHP Version 5.6.40

      These are the errors I get trying different hostnames that I've found on the forum

      smtp.office365.com
      authentication failure [SMTP: STARTTLS failed (code: 220, response: TLS go ahead)]

      ssl://smtp.office365.com
      Failed to connect to ssl://smtp.office365.com:587 [SMTP: Failed to connect socket: fsockopen(): unable to connect to ssl://smtp.office365.com:587 (Unknown error) (code: -1, response: )]

      tsl://smtp.office365.com
      Failed to connect to tls://smtp.office365.com:587 [SMTP: Failed to connect socket: fsockopen(): unable to connect to tls://smtp.office365.com:587 (Unknown error) (code: -1, response: )]

      I tried this patch which actually started sending emails when I disabled SMTP. But they go to junk which isn't very professional and it could possibly stop working at anypoint because it's unsecure.
      https://stackoverflow.com/questions/39653578/osticket-and-office365-smtp-authentication-failure/39791653#39791653

      I used mxtoolbox.com to find the hostname that ends with .mail.protection.outlook.com
      Could not get SSL to work, but did get SMTP working without authentication.

      4 days later

      @emoreno double check your logs and Default MTA setting. When I disabled authentication, it seemed to accept the settings (even though my server requires authentication), but in fact it was logging and error and defaulting the use PHP mail function. What ended up working for me is the following:

      1) Update* osTicket's mail class at /include/pear/Net/SMTP.php changing line 176: $this->socket_options =$socket_options; to $this->socket_options = array('ssl' => array('verify_peer_name' => false));

      2) Add the required emails to Cpanel with the same password as in Office365.

      3) Use http://www.mail-tester.com/ to test for errors (which led me to fix the following deliverability issues)

            A) Edit the domain SPF record

      B) Add a dmarc TXT record to the domain

      Replies by my Agents in the UI go to junk. I'm hoping the SPF record hasn't been updated yet and when it does it will solve the problem.

        welltecnologia this worked for my Office365 mail setup. If you host your own exchange servers, you may have other settings that need to be adjusted.

            harbpaul This problem has been going on for years ...
            To this day, they have not found a solution.

            Impressive....

            I've tried Gmail, nothing works on that ...

            I have been struggling with this problem for 3 years ....

              @welltecnologia I know gmail can be tricky, it gave me a headache on another system. Since you have been working on this for so long, I'm sure you Enabled Less Secure Apps in your Gmail Settings? Another issue I faced was communication between the Web Host and Office365, they use the same ports and the web host didn't allow SMTP traffic on those ports. That's why I created those emails in my Cpanel to send from the webhost.

              3 months later
              7 months later

              This patch can solve the issue:

              diff -ru osticket.orig/include/pear/Net/SMTP.php osticket.fixed/include/pear/Net/SMTP.php
--- osticket.orig/include/pear/Net/SMTP.php	2020-12-07 19:23:52.000000000 +0100
+++ osticket.fixed/include/pear/Net/SMTP.php	2021-02-13 09:58:08.821455158 +0100
@@ -569,7 +569,7 @@
          * STARTTLS extension, and aren't already connected over a secure
          * (SSL) socket connection. */
         if ($tls && version_compare(PHP_VERSION, '5.1.0', '>=')
-            && extension_loaded('openssl') && isset($this->esmtp['STARTTLS'])
+            && extension_loaded('openssl') && $this->esmtp['STARTTLS']
             && strncasecmp($this->host, 'ssl://', 6) !== 0
         ) {
             /* Start the TLS connection attempt. */

              Regards,
              Anthony Ananich
              https colon slash slash ananich dot pro

                17 days later

                anthony1 Hi Anthony, i tried to comment line with -- and add other line, bu the problem for me persist. I ve used a PHP 7.4.13 and IIS with Windows Server 2019.
                May you help me?

                  6 months later

                  /include/pear/Net/SMTP.php

                  Line 176: Replace $this->socket_options = $socket_options; TO
                  $this->_socket_options = array('ssl' => array('verify_peer_name' => false));

                  Line 572: Replace && extension_loaded('openssl') && isset($this->esmtp['STARTTLS']) TO
                  && extension_loaded('openssl') && $this->esmtp['STARTTLS']

                  All problem solved for my case
                  OSTICKET: 1.15.3.1
                  PHP: v7.3.25

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