Access and Refresh Token

Thought I would give some clarity on error codes you might get:

When Access token has expired, you’ll get 401 Unauthorized with the following message in body:
    {
        "success": false,
        "error": "Invalid token: access token has expired"
    }

When Refresh token is invalid, you’ll get 400 Bad request with the following message in body:
{
    "success": false,
    "message": "Invalid grant: refresh token is invalid"
}