Hi @mikel1,
If you’re experiencing this issue still after checking the users and conversations (in your case, ‘Chat User’) collections, collection permissions correctly like @Ali-Bazzi mentioned, check these suggestions. : Unauthorized Error When Creating Conversations - #3 by dilon_perera
If you can share some more details of your setup along with some screenshots or a screen recording, that would helps us a lot to identify the issue.
Let me know of how it goes!
Thank you and have a great day!