Update a few days later: I was able to log in. Maybe it was because I had a new account? Who knows, but it is working now. I was able to log into the web based messenger, even without the apps still installed (I uninstalled the app as the web based messenger is what I am interested in)
Next day update: The Web based got quite buggy on me. When trying to sign in, I kept getting an error message saying “Too fast. You are performing too many actions. Try again later.”
I am in the stone age when it comes to apps, so this is a real reach for me. Maybe what I just learned may help others who are reluctant to change to a new messenger service.