Same here. I have the app loaded on my Android phone, and when I try to log in, I get
We've encountered an error.
Please try again. 
I'm able to log in using the web app, so I know my username/password is correct.
I called customer support, and was on hold for nearly an hour, got bounced to three CSR, then they dropped my call.
I've had HOME for two days. Tomorrow they get a call to have it yanked out if this doesn't get fixed.
I uninstalled and re-installed the app, and now it works.
By the way... When talking with Comcast customer service, I gave them my contact number "in case we were disconnected..."
Yeah right - still waiting for that call back...
Your broadband and celluar network connectivity (on your touchscreen) keep going doing and your broadband is currently down. Can you please try resetting your cable modem: http://customer.comcast.com/help-and-support/internet/power-cycling-your-modem/