Incoming call fails on Apple Watch with cellular.
I have an SE iWatch with cellular (version 9.6). My watch started showing "Called Failed" on in-comming calls. I rebooted my watch and iPhone at which time my iWatch did not take in-comming calls. I went to the watch app on my iPhone and clicked on cellular. I then clicked on my cellular plan which gave me a pop-up to manage or remove the plan. I clicked on manage the plan and the app appeared to reload the plan. I tried an in-comming call and the watch worked correctly. Not sure why the cellular was missing of lost.
Apple Watch Series 8, watchOS 9