The default certificate is used for IMAP connection when the Plesk Premium Mail is installed

Symptoms

• The default certificate is used for IMAP (993) connection when the Plesk Premium Mail is installed in Extensions > My Extensions:

  # openssl s_client -showcerts -connect exmple.com:993 -servername example.com | grep CN
  ... O = Plesk, CN = Plesk, emailAddress = info@plesk.com

• But SMTPS (465) connections are secured with correct SSL taken from Domains > example.com > Mail Settings:

  # openssl s_client -showcerts -connect exmple.com:465 -servername example.com | grep CN
  ...CN = example.com
  

Cause

SNI configuration was broken for domain example.com

Resolution

1. Log into Plesk.

2. Go to Subscriptions > example.com > Customize and temporary enable the options below in case they are not enabled:

   • Plesk Premium Mail
   • Plesk Premium Mail - Free

3. Go to Subscriptions > example.com > Plesk Premium Email and press the button Fix.

   Note: This step can also be performed directly via Plesk > Premium Email > example.com > Click on the arrow to open the additional information

4. If Plesk Premium Email should not be used for example.com, disable it's settings back in Subscriptions > example.com > Customize:

   • Plesk Premium Mail
   • Plesk Premium Mail - Free