hi team. i am currently struggling with the cron set up. here is my current build:

Server Information
osTicket Version v1.12 (a076918) — Up to date
Web Server Software Apache/2.4.29 (Ubuntu)
MySQL Version 10.1.40
PHP Version 7.2.19-0ubuntu0.18.04.1

admin panel - emails - settings:
Email fetching enabled
fetch on autocron enabled

admin panel - emails - settings (on the mailbox of choice):
fetching email via imap or pop enabled

I have used the following guide - https://www.easycron.com/cron-job-tutorials/how-to-set-up-cron-job-for-osticket up until and including step 3. at step 2 i renamed and moved the rcron.php file from /var/www/html/osticket/scripts to /var/www/html/osticket/upload. its name is now mailcron.php

i updated this script at line 24 and 25 (via winSCP) to:
'url'=>'http://10.200.1.78/osticket/upload/api/tasks/cron',
'key'=>'CF115921761146C69A727955105C7DAF'

http://10.200.1.78/osticket/upload/ is used to access the user panel as well.

via putty / cmd line i then ran the crontab cmd:

/5 nobody /usr/bin/php /var/www/html/osticket/upload/mailrcron.php
/5 root /usr/bin/php /var/www/html/osticket/upload/mailrcron.php
and even the below as per a forum suggestion:

/5 /usr/bin/php /var/www/html/osticket/upload/mailrcron.php
5 * /usr/bin/php /var/www/html/osticket/upload/mailrcron.php

(edit - the stars arent showing up but they are there - star/5 star star star star)

needless to say, no emails are being fetched and converted to tickets while my agent account is logged off from the scp.

currently it is set to /5 * nobody /usr/bin/php /var/www/html/osticket/upload/mailrcron.php

i checked /var/log/apache2/error.log and there was nothing there except me restarting the the cron service and even the server itself. i then checked var/log/syslog where i found

Jun 25 10:05:01 OSticket CRON[16457]: (root) CMD (nobody /usr/bin/php /var/www/html/osticket/upload/mailrcron.php)
Jun 25 10:05:01 OSticket cron[10806]: sendmail: fatal: open /etc/postfix/main.cf: No such file or directory
Jun 25 10:05:01 OSticket postfix/sendmail[16458]: fatal: open /etc/postfix/main.cf: No such file or directory
Jun 25 10:05:01 OSticket CRON[16456]: (root) MAIL (mailed 30 bytes of output but got status 0x004b from MTA#012)

i then installed postfix via cmd line and navigated to etc/postfix and renamed main.cf.proto to main.cf

restarted the cron service and i am now getting

Jun 25 10:20:01 OSticket CRON[16667]: (root) CMD (nobody /usr/bin/php /var/www/html/osticket/upload/mailrcron.php)
Jun 25 10:20:01 OSticket cron[16658]: sendmail: fatal: bad string length 0 < 1: setgid_group =
Jun 25 10:20:01 OSticket postfix/sendmail[16668]: fatal: bad string length 0 < 1: setgid_group =
Jun 25 10:20:01 OSticket CRON[16666]: (root) MAIL (mailed 30 bytes of output but got status 0x004b from MTA#012)
Jun 25 10:25:01 OSticket CRON[16676]: (root) CMD (nobody /usr/bin/php /var/www/html/osticket/upload/mailrcron.php)
Jun 25 10:25:01 OSticket cron[16658]: sendmail: fatal: bad string length 0 < 1: setgid_group =
Jun 25 10:25:01 OSticket postfix/sendmail[16677]: fatal: bad string length 0 < 1: setgid_group =
Jun 25 10:25:01 OSticket CRON[16675]: (root) MAIL (mailed 30 bytes of output but got status 0x004b from MTA#012)

kinda stuck here and looking forward to any suggestions
thank you in advance!