I was able to solve this, are you still stuck?
@daMask I have fixed some levels but still have not gotten the complete solution.
https://community.shopify.com/c/shopify-apis-and-sdks/how-to-register-carrierservice-to-app/m-p/1543378/highlight/true#M78767
That linked issue looks different to the one I was having.
@daMask you can post your questions with full detail so else can help you.