I have been using osTicket without any issues and then on Monday it stopped downloading e-mail messages. When I dug into the issue a little more, I see that Microsoft decided to disable SMTPAuth (for example), which at least explained why I couldn't send out e-mails from the ticketing system. However, it also fails to download the e-mails as well. Nothing has changed in the environment. In an attempt to resolve the issue, I updated the ticketing system to 1.17.2 with the latest .phar plugins. But it's still not working. I'm still getting the error message:
5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information.
I have a ticket in with Microsoft on this.
For Remote Mailbox, I get this error message:
cannot select INBOX, is this a valid transport?
Any troubleshooting I can do to isolate the issue?