Plesk notification emails not sent to Plesk administrator external mailbox

Symptoms

• Plesk notification emails not sent to Plesk administrator
  external mailbox

• /var/log/plesk/panel.log file contains the following:

  ERR [panel] '""' is not a valid hostname for the email address:

Cause

Email address misconfiguration.

Resolution

1. Log into Plesk

2. Go to Plesk > My Profile, rename admin email address, click Apply and then rename it back to original, and click Ok