I keep getting a message about "active time". When I try to log in to Xfinity on my iPhone (for the very first time), I get a message that I should use xfinity.com to log in. I checked OK. When I put in my xfinity username and password, I entered the xfinity.com username and password, which works on my PC. I get a message that my username or password is incorrect. How do I log in?