The symptom of this issue is an inability to connect to email through an email application, and/or a mobile device repeatedly notifying a user that a particular server cannot be trusted or verified.
Example:
To remedy this, please update your incoming and outgoing mail servers on each of your affected email accounts to the following:
Incoming Server: yourdomain.com
IMAP Port: 993
POP3 Port: 995
Outgoing Server: yourdomain.com
SMTP Port: 465
Also, you can login to your cPanel and check your email settings by clicking Email Accounts > Set Up Mail Client. From there you can view the correct settings for your account and much more.
If you continue to have problems, please submit a support ticket and we will be happy to help you.