Unlock ATT iPhone 7+

www.att.com/deviceunlock

Apply for unlock as a non-customer.

Hopefully, whoever sold you the phone paid it off. If not, it may not be able to be unlocked.

This is the answer I get:

The device you want to unlock is active on another AT&T account. The account owner needs to remove the device from their account first. For assistance, call 800.331.0500.

Hello bobdizzle, we're here to help you with your unlock request.

The device you want to unlock is active on another AT&T account.

That’s your Consumer Cellular account. You need to get that device removed from that account.

An AT&T community specialist helped me get it unlocked.  It was not locked by Consumer Cellular, by the way, as I did not buy it from them so they had no reason to lock it. Thanks.

You’re right, Consumer Cellular didn’t lock it.  It was an AT&T locked phone before you got it.  However, the other account message isn’t wrong.  When you use a MVNO that uses the AT&T cell network, AT&T creates a account to be able to use the phone on their network, but it’s not a normal AT&T account.  That’s why you almost always get the “active on another account” message when you’re using a MVNO on AT&T, but not AT&T itself as the carrier.  Glad that AT&T CS was able to get it removed for you.

Thanks, dwill05. This unlock stuff is a little tricky to understand.  Thanks for helping in that regard.