SMTP Errors

didierblaylock

I'm having an issue with sendmail. I get the attached error consistently in the logs.
.

Fetching mail works fine and it will generate a ticket based on that email.
I did have a certificate expire and had to renew it and also create a new app registration on O365. It was working prior to that. I've already updated the configurations for OAuth2 and both of those testing successfully. Default MTA is set to None: Use PHP mail function.

However, it won't send. Can anyone provide any assistance?

KevinTheJedi

didierblaylock

Sounds like SMTP is failing or the email sending the mail does not have SMTP configured so it’s falling back to local Sendmail which apparently not configured in your instance. So the fix is to figure out what’s going on with your SMTP, fix it, and retest. Try checking other logs in the system logs or maybe php/webserver error logs for any related errors.

Cheers.

didierblaylock

I modified the php.ini file to include the proper address and got a STARTTLS error. I added the tls:// preface to the mail server address but I'm still getting the error below.
Unable to email via Sendmail Unable to send mail: mail(): SMTP server response: 451 5.7.3 STARTTLS is required to send mail [BN0PR04CA0088.namprd04.prod.outlook.com 2026-07-08T15:20:25.725Z 08DEDCB3E7277509]

KevinTheJedi

didierblaylock

Since you appear to be attempting to use O365 (which now requires modern auth [OAuth2] to send mail via encrypted SMTP) the ideal fix is to configure proper SMTP for the system email sending mail via the helpdesk UI. The Email Settings Guide is here and the Microsoft OAuth2 Authorization guide (email) is here. If you desire to continue with sendmail then you need to look at guides online that explain how to configure sendmail with O365 as that's outside the scope of osTicket.

Cheers.