Describe the Bug

I'm using custom DNS solution (as part of tailscale), and I have "jellyfin" itself as a valid domain - I can type http://jellyfin and it will open up jellyfin in my browser.
The regex check in MALsync doesn't accept domains without TLDs

Steps to reproduce the behavior

Try to add a domain without tld as a custom domain, for example http://jellyfin

Browser

Vivaldi 6.1.3035.302 ( Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36)

Type

Extension

URL

http://jellyfin