Getting OAU-149 error

TokenInvalid OAU-149 cause due to various reason:

• You token got corrupted, some space or unwanted character added into it unknowingly, or some character is missed while copying the token
• The token is only valid for your sandbox environment but used in some other environment like production environment. Though the token is valid but invalid for production, Make sure you are not doing that.

I already answered this here in the community: https://forums.developers.ringcentral.com/questions/9525/tokeninvalid-oau-149-error.html