I have subscribed to the Collections product, and trying to test the request to pay (v1_0/requesttopay) in sandbox. I am setting the callback URL in the header of this request. Using the same domain I had provided while creating API user.

The callback URL allows both HTTP and HTTPS, both PUT and POST is also allowed.

The payments requests are getting accepted and when I do a status check they are successful. But I am not receiving any callbacks. I have tried sending multiple payment requests but did not receive callback for any of the request.

Example request payload:

URL: https://sandbox.momodeveloper.mtn.com/collection/v1_0/requesttopay

Request payload:

{"currency":"EUR","amount":"15","externalId":"b5926558-cd36-40fa-b455-67ef5e97d2e5","payer":{"partyIdType":"MSISDN","partyId":"22933123466"},"payerMessage":"Wallet Recharge","payeeNote":"Wallet Recharge"}