xfinity app log in issues on iphone

I have been thru tech support several times.  I have downloaded the iphone xfinity app on iphone 15.  When asked to enter my Xfinity ID i enter it and hit "lets go" and the app loops back to sign in with your xfinity ID.  It will not allow me to log in.  I would like to control my router, and it appears the app is the only way to do so.  Very frustrating.  I believe its the app and need update.  Any help?