see update to original post - has solution.
@rachel3223, we had all antennas attached and had tried an external antenna setup and then back to the stubbies. No idea what was broken, but something is broken in our first Max Transit Cat-18. Second unit just worked!
@mhm33 so same sim and plan but new transit fixed it?
Did you have the same fw on both and same hw revision?
Same SIMs and plans on both routers. Old had been factory reset and still failed. Not sure of original FW, but both upgraded to 8.1.2. HW version 2 on both. I think simply a broken router.
ok thanks for the update.