Getting error: USER_AUTHENTICATION_FAILED on create envelope

[lovelight24]

Hello Mr. Tucker,

I am using laravel 5.6 and laravel-docusign api version 2.

I checked the sandbox credentials and integrator key, all are corrected.
When we call create envelope function then I got an error

Error while requesting server, received a non successful HTTP code [401] with response Body: O:8:"stdClass":2:{s:9:"errorCode";s:26:"USER_AUTHENTICATION_FAILED";s:7:"message";s:49:"One or both of Username and Password are invalid.";}

Please help to resolve this issue.
Thank you