my simple solution to "Can't establish a reliable data connection to the server" when add account to Android

My android version: 4.0.4

I can not add account either in Play Store or in Youtube app as searched online, or in Settings-->Accounts & Sync.

tried in browser I can browse websites, also I can login to my google account from desktop.

accidentally,I turned on "Wi-Fi direct" and it automatically turned off WiFi, then I turned off "Wi-Fi direct",

turn on WiFi again, try to add account in Settings-->Accounts & Sync, it works! then I tried in Play Store, it also works.

so essentially it probably just to reset your WiFi connection.

so if you have this issue, try this simple solution first instead reset your phone to factory default or root your phone.