password problems

I have password synchronization problems.  I have Xfinity Home Monitoring (Home Security).  Every once in a while, this app on my smart phone logs me out, and I can't log in, even though I'm using the correct password.  Finally, I have to select forgot password (even though my password is correct), and go through the steps to change my password, and then it works.  I also found out that when I can't log in with my correct password on the app, I can log in to Xfinity on another device with that password, and then change it.  But one time when I did this, my email kept telling me I had an incorrect password (even though I changed it in Thunderbird also -- I use SMTP).  I finally found out I had to click on a message from Xfinity in Thunderbird from when I was trying to change the password, and then it worked.  This happens once a month or so.  Please fix the problem.  I need the Home Security app to work all the time, so I can arm and disarm the system (although I can also use the touch pad mounted on the wall at home).  I tried calling Xfinity on the phone, but there's no one to talk to that's knowledgeable about that problem.