Why dows my at&t phone keep saying off line

[AC Question]

Everytime i try to use my at&t phone its repeatedly states off line i have turned my phone off an removed the battery an it still states off line.How can i fix this problem.

 

[B. Diddy]

Welcome to Android Central! Which phone? Do you mean that it's not connecting to the web via 3G/4G mobile data?