400 Bad Request

[mtvbrianking]

Callback URL

• If the X-Callback-Url header is present, it can't be empty
• A wrong callback URL will result in an error

Sandbox
Your Callback URL host must match the ProviderCallbackHost you registered.
You can validate the latter using the ValidateApiUserId endpoint.

Live
You must register your callback URL on the MTN Partner Portal first.
You may need to write to your MTN account manager to allow / whitelist your callback host - in case you're not receiving callback, but collections are successful