Does the message "can't establish a reliable connection to the server" pops up when you try to sign in. Here are few fix for the problem.
Asus released lollipop update for some of its ZenFone series Smartphones. A simple tutorial to update Asus Zenfone smartphone to Android L.
Android Device is giving error on clicking update software? Pop ups "Cannot update software, your device has been modified" fix on problem
After upgrading Samsung Galaxy Grand Duos update to Android Jelly Bean 4.2.2 got much bugs and problems, here is solutions to fix those bugs