"Sorry, we're having some trouble" activating modem from Xfinity app - do NOT want to call or chat to activate

@raviC 

This used to work in the app for me. Now I'm just getting the "Sorry," message. I know I can call in or chat to activate. I don't want to do that. Calling or chatting with Comcast/Xfinity takes what should take 10 seconds and turns it into a 30+ minute waste of time.

I'm having some trouble getting my router to work nicely with a  new modem, and the new modem is not giving the speed it should so I need to do a little troubleshooting which I can do on my own, but if done through an Xfinity agent will take until the heat-death of the universe to complete.

Is there ANYTHING that can get this working in the app again? I've uninstalled and reinstalled. I've logged out and in. No luck. 

You are going to need to activate the modem before you set it up with your router, especially if it's a new modem that you recently bought and are trying to set up.  So, however you need to get it activated, that needs to be done first.  And, this is an approved modem on Comcast's list?  Also, is this a brand new modem or one you purchased second hand?