We have an iPhone that is dropping off my W31 network (base and 2 satellites),  I have seen on the Apple forum that a DTIN setting on the W31 maybe set at “3” and for the iPhone to work properly it should be set on “1”.  How to I change that setting or verify that is not my issue?

I have multiple PC’s other iPhones, iPads etc that are not dropping.  Everything has been reset multiple times…   Thanks, frustrated!!!