If you use Let's Encrypt or Comodo/Sectigo SSL with domain name, you may experience connectivity issues. Email server no longer accepts LEA and Comodo SSLs. It doesn't impact email delivery and processing, only SSL connections. Emails are being processed normally.
Your options are:
- check email via full server ID (it works);
- check email accepting SSL warnings.
cPanel technicians are looking into this right now and we expect hotfix within next 24-48 hours.
We do apologize for the inconvenience.