Spoke too soon. This brings up share windows, but any link sent through email will be a dead link (unavailable or user stopped sharing), and it will not execute imessage.

A few methods deprecated, but this approach still works. This is the simplest example I have seen. Thanks

I have spent a couple days on this issue. I also tried going back and forth from default container id to using the identifier. I am using an example found from iOS Academy (https://www.youtube.com/watch?v=Og-2A5n5IAY). I was able to get it to work once, but repeating the exercise in a new app copied exactly from the previous one, with exception of changing the app and container name resulted in the same error messages. There seems to be some very random happening. Now I cannot get it to work at all with the same code.