On attempt to open a certain file in Plesk File Manager, the user is forcefully logged out from Plesk without the ability to log in back on the same page.
The Plesk URL login page is served by Cloudflare:
If the server IP address is used as a login URL (https://203.0.113.2:8443 ), the issue is not reproduced.
Cloudflare settings prevent opening certain files.
Contact Cloudflare support for troubleshooting.
As a workaround, use one of the following options:
Disable Cloudflare support for example.com.
Log in to Plesk using a Plesk IP address instead of a hostname.