This post is to let our developer community know that we're aware of a 500 error page occurring when trying to generate access tokens with new Mashery API Keys. We're currently investigating and trying to resolve the issue.
Thank you for your patience.
Partner API Support Engineer
This issue has now been resolved. If you generated an API Key yesterday that is still not working, login to Mashery to delete the key and create a new API Key. Thank you for your patience.