There are now patches to apply if you don’t have any problems making calls on an AT&T iPhone 18 Pro Max. If you do, you need to get your phone replaced.

iPhone 18 Pro Max

iPhone 18 Pro Max
Since launch, iPhone 18 Pro Max models have been dropping off the AT&T network. In some cases, never to return.
After an OS update earlier in the week, and a carrier settings update on Friday, the problem may no longer manifest for those who haven’t seen it. But, that doesn’t help if your iPhone has issues already.