Solution
To setting, you must go to the Android Settings', then open these two applications - 'Services Google Play' and 'Play Store' - where you have to 'Clear Cache'. Once you have done this for two, go into the menu 'Accounts' and delete your Google Account. Then restart your mobile, then sync back to your Google Account, then let your mobile 5 minutes without touching it. After these 5 minutes tranquility of your Android, the -501 error should not bother you.
edit