SandBox and Production Mode doubt

I’m getting invalid subscription key invalid while testing it in sandbox mode 
while testing it with live url it give resource not found.

Below is for sandbox Mode.
URL :: https://sandbox.momodeveloper.mtn.com/v1_0/apiuser
headers :: {Authorization: Basic ZmY5NTZkMGYtODYwOC00NmZhLWIzMzEtZjRkNDhmNzAwZTNiOm51bGw=, X-Reference-Id: ff956d0f-8608-46fa-b331-f4d48f700e3b, Ocp-Apim-Subscription-Key: 84dbf7a8a0e44923988a0dd621169ec6, Content-Type: application/json}
 MtnMomo :: body :: {providerCallbackHost: https://dulu.cm/success} [log]
MtnMomo :: apiuserAPI :: 401 :: { "statusCode": 401, "message": "Access denied due to invalid subscription key. Make sure to provide a valid key for an active subscription." }


Below is for live testing 
URL :: https://proxy.momoapi.mtn.com/v1_0/apiuser
headers :: {X-Reference-Id: 6e1fcdda-0cb1-4a85-8af6-8e3e6ff31942, Ocp-Apim-Subscription-Key: 0144c9f7b7774f4b8108cc4b243561b6, Content-Type: application/json}
body :: {providerCallbackHost: https://dulu.cm/success}
apiuserAPI :: 404 :: { "statusCode": 404, "message": "Resource not found" }