When trying to configure a mailbox using port 143
Errors in the maileater_nxd log show:
2021-06-21 20:44:36:648 ERROR [ForkJoinPool-1-worker-1] c.c.S.m.c.JavaMailIMAPClient - Failed to make connection with STARTTLS to server outlook.com, port 993, trying SSL connection
2021-06-16 08:41:45:382 TRACE [ForkJoinPool-1-worker-2] c.c.S.m.ConnectSession - [mailbox:MAILBOX:400979] Failed to connect to IMAP4 server outlook.com at port 993
Appears even though port 993 is not configured.
Release : 17.x
Component : Svc Desk Email
Mailbox in Microsoft365
STARTTLS tries to form an insecure connection first then a secure connection.
This is why we see a connection attempt using port 993.
Port 143 is the insecure port and port 993 is the secure port.
If STARTTLS unsuccessfully tries to connect using IMAP insecure port 143, then by design it tries to form a secure connection using port 993.