- The server was upgraded to Plesk Obsidian;
- Before the upgrade, there was domain without hosting, only email accounts, that were accessed through webmail via HTTP;
- After the upgrade, webmail is redirected to HTTPS as a result webmail shows invalid ssl warning.
This is Plesk bug with ID PPPM-11114, which is planned to be fixed in one of the future product updates.
Follow the article to be notified when the bug is fixed - the article will be updated.
- Log into Plesk.
- Switch on hosting: go to Domains > example.com > Hosting settings > click Change and set Hosting type to Website hosting ;
- Install the certificate for webmail according to the article How to secure webmail using Let's Encrypt in Plesk Onyx;
- Switch off hosting: go to Domains > example.com > Hosting settings > click Change and set Hosting type to No web hosting.