- Plesk for Linux
Note: This article has the reference to the issue with the fix available:
It is not possible to enable Permanent SEO-safe 301 redirect from HTTP to HTTPS from a customer's account - the checkbox becomes unchecked again after applying the changes.
Such behavior is caused by a known bug with id #PPPM-5434 . It will be fixed in future Plesk updates.
As a workaround use Plesk administrator's account to enable the option Permanent SEO-safe 301 redirect from HTTP to HTTPS at Domains > example.com > Hosting Settings