@robyn
Make sure the desktop file is installed, normally it should be:
/usr/share/applications/strawberry.desktop
Make sure that strawberry is installed in PATH, and that it isn't a different version from the one you launch.
sudo find /usr -type f -name 'strawberry'
Make sure the "tidal" URL scheme is correctly registered to strawberry, run the following command in a terminal while strawberry is open:
xdg-open tidal://test
This should add "tidal://test" to the active playlist. If that works, then it means authentication with TIdal should be possible.
If it still doesn't work, then try close firefox and reopen, or set a different web browser as default.