- Unable to send or receive e-mails from remote mail addresses.
- Customer in Plesk is unable to access Plesk Email Security extension, the following error message is displayed:
PLESK_ERROR: Hostname is not valid. Please set a hierarchical, dot-separated domain as the hostname!
The server hostname must be a fully qualified domain name (FQDN).
Go to Tools & Settings > Server Settings and set a Full hostname.
If hostname already set, change it to some random one (ex. test.example.com) and then change back to correct hostname.
Open Plesk Email Security in Extensions > My extensions > Plesk Email Security > Open
Click the button Install Now!