cannot connect to gmail

[AC Question]

Why cant i connect to my gmail?I am using samsung j1 2015 I reformat my phone because theres always popping "The ... com.android.phone..." so I reformat it but I cant open my google apps because my gmail is not working even my username and password is correct its still not working so I cant use google apps please help me

 

[B. Diddy]

Welcome to Android Central! You did a standard factory data reset from the Settings>Backup & Reset menu? Are you saying you can't open the Gmail app, or add your Gmail account to the stock Email app? Or is the phone asking for a Google username/password immediately after the factory reset, and it's not accepting what you enter?