- Plesk for Linux
- The following error occurs while connecting to an email account at mail.example2.com using email client application:
This site attempts to identify itself with invalid information
The target principal name is incorrect
- Mail Server is secured with Let's Encrypt SSL certificate issued for example1.com via Plesk Panel extension.
- Server's hostname is the hostname.com and it is resolvable from the internet.
Mail is secured with a certificate which does not contain the information for other domains.
If the mail server is secured using an SSL/TLS certificate issued from a particular domain, the domain name must be specified in the email client settings as the incoming/outgoing mail server, for correct sending and receiving of emails. Refer to the following documentation .
In order to resolve the issue change the certificate for securing email server with the one which issued for the server's hostname hostname.com:
1. Go to the Home > Tools & Settings > SSL/TLS Certificates > Let's Encrypt
2. Put hostname.com into the Domain name filed and press Renew.
3. Go to Tools & Settings > SSL/TLS Certificates . Click Change near the Certificate for securing mail field and select Lets Encrypt certificate (server pool) and click OK.
4. Manually set server's hostname during configuration of mailbox in a mail client instead of domain's name.
Alternatively, the resolution from this article can be used.