Rest API for Paypal Deposit - 401 ERROR

[Vi-C]

I am trying to make USD deposits in my platform, and using Paypal Rest API. When trying to make the deposit after making all the needed connections on my end, my platform is telling me that there is a paypal connection error.

{\"error\":\"invalid_client\",\"error_description\":\"Client Authentication failed\"}

So in this case I am not sure if I need to activate any web hooks for this to work properly? or any other suggestions would be highly relevant to getting us connected.

Thank you.