LG OPTIMUS E975 LTE not working with AT&T sim( No internet)

[jibu chandran]

I have a new unlocked LG optimus E975 phone( LTE).
Internet does not work with ATT LTE $60 Plan on my phone. They have tried different APN settings but nothing worked. Anyone knows what the issue is? Please help:'(

 

[pkcable]

I looked up the specs it has the right frequencies. Are you sure it's properly unlocked?