Customer api returns Error: 401 error connecting to the API (https://api-sandbox.dwolla.com/customers)

Hello,
I am creating customer through api by PHP to make transfers using sandbox account. I am using $customer = $customersApi->create method. But I get the error: 401 error connecting to the API (https://api-sandbox.dwolla.com/customers). Why am I facing this error? Please help.

Hi @symapptest5

Please make sure you are utilizing your sandbox key and secret in your Client. This php repo contains an example in the readme.