Can't sign into Xfinity Home

I have been having this problem all year.  I have the Xfinity Home app on my Android phone.  I don't use this app. that often -- mainly when going on vacations.  After I am logged in for a couple weeks, it disconnects and I can't log in again.  I go to log in, and after I press the "Sign In" button, it just goes back to the sign-in screen again.  It doesn't say my password is wrong - just won't let me sign in.

I'm sure my email and password are correct, because I can log out from Comcast on my PC, and log in using that email and password and it works just fine.  And I am logged into the Xfinity app. on my smart phone -- that works fine as well.

If I want to log in, I found out that I have to go on my PC and change my Xfinity password, and then I can log in with the new password, until it disconnects in a few weeks.  But when I do that, I have to change the log in password for all the devices I connect to my Comcast account with.  The only thing I haven't tried to correct the problem is to uninstall the app. and reinstall it again.  So I need to use the keypad in my house to arm and disarm the alarm when Xfinity Home is not working.  Please help.  This is annoying.