cPanel have pushed through updates to IMAP and POP3 which means that older clients may have issues connecting.
This primarily affects clients which only support TLS 1.0/1.1 and insecure ciphers. Usually seen with Outlook 2010, WIndows 7 and OSX El Capitan or older.
Much of this software is extremely old and unsupported by the vendor and should be updated immediately. Where this is not possible, we recommend trying an alternative mail client such as Thunderbird which often includes its own TLS engine which works with current TLS 1.2/1.3 standards.
We appreciate the impact this has had and have raised our concerns with cPanel about them not giving any prior notice to the change.
Due to the security benefits this provides and that from our log analysis less than 1% of mailboxes are attempting to login with invalid TLS settings, we will leave these changes active instead of re-enabling insecure connection methods.
