Outlooks Not able to connect to the Server to fetch and Send Email after cPanel update.
With the recent cPanel update it came into light that recently cPanel decided to make some changes to its TLS ciphers and that in turn had many users not being able to fetch and send emails via Outlook anymore.
Some of the common errors that we noticed is the 0x800CCC1A
I have been facing the same issues since the last couple of weeks. When finally cPanel decided to discuss the same in a Forum post. Link here
The best solution yet is to manually change the TLS cipher list and enable the Legacy settings which will get all on track.
Fixed case CPANEL-11108: Remove Triple DES from default cipher suite.
You can browse to “WHM >> Exim Configuration Manager >> Advanced Editor” and change the “tls_require_ciphers” value to the following value that was issued by default in cPanel version 64:
ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS
****However, keep in mind this is unsupported and not recommended due to the negative impact on the server’s security. Instead, the recommended solution is to upgrade systems using Windows XP to a supported OS (Microsoft no longer provides security updates or technical support for the Windows XP operating system).
However it resolve the issue until there is a new update is released with the fix.
If the issue still did not work it is best if you ask your Hosting Provider to check this out.