- 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 in Domains > example.com > Hosting Settings from a client's account - the checkbox becomes unchecked again after applying the changes.
Such behavior is caused by a Plesk bug with id #PPPM-5434 which is fixed in microupdates.
Install Plesk microupdates.