AT&T SIM/service working but cannot update "wan connection settings".

I have two SIM cards in my Pepwave MAX Transit (verizon and AT&T prepaid). Up until a few weeks ago, both SIMs worked correctly and I had access to WAN connection Settings.
Now Verizon SIM is still ok, but although the AT&T service is working, I cannot update ‘wan connection settings" for the AT&T SIM. When iI select “save and apply”, I get the following message : “Unsupported value: cellular sim mobileType” and no parameters’ can be changed from my original settings.
Saving config and then going back to factory settings did not help.
I am running the latest Pepwave firmware: Current firmware version: 8.3.0
any help waul be appreciated,
thanks
Joe

joe,
I see that message when the 3g / lte is set to anything besides Auto. Is it possible you have it set to LTE only? I’m on a Max Transit Cat 18.

thanks so much…yes, the 3g / lte setting was set to lte, when I set to auto all is ok
Joe
BTW: I’m on a Max Transit Cat 12