invalid resource owner credentials

Hello,

I recently had an application promoted to production status, however I cannot get the api to work using the production credentials. I have already changed the url to https://platform.ringcentral.com and am using the appropriate app credentials for production and not sandbox. Using Fiddler, I can the error message returned as

I am using the appropriate user credentials as well. I am able to log into service.ringcentral.com using the production user credentials.

Does something else need to be configured?

Thanks