Hi , I have been facing the same issue and couldnt able to get any support from the community nor from mtn momo.

​@Boopalan - hmm i hope they get to respond to this post. it would be great to integrate momo into our applications. Otherwise we'll go with the other alternatives

​@Boopalan  - I figured it out… that “Receive Mobile Money payment” collection is either deprecated and the site never updated. Or it has issues and no one is talking :D

Just subscribe to another collection instead of that one. And use their keys. You’ll be all set!

Thanks for the advice! I switched to a different collection and got things working in the sandbox.

I’m now trying to move to production – how did you manage to get the API user ID and API key for that? The docs mention the partner portal, but I haven’t received any details on accessing it yet.

 Appreciate your help!