@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.