Sorry, but what is 'Adobe Render'? Never heard of it.Can you give more details on what are you trying to achieve? This community has AEM knowledge, however you would need to help us with Adobe Render and DC.  

You can't have AEM (or any application) as both SP and IdP From your description it seems to be that you are probably using AEM as SP, since you are trying to fetch access token in it.Here's a sample project where AEM (as SP) is integrated with Linked (as IdP) for users to login using OAuth. This s...

This seems like a custom implementation for OAuth, is it? I suppose you're using AEM as a (SP) Service Provider? If so, what IdP (Identity Provider) you are integerating with?Generally the IdP would provide API or tech documentation on how SP can consume different tokens from it.I'll wait for the ab...