Need help! Pinterest API oauth access token

Hey everyone, I was hoping someone out there had experience setting up the pinterest API or plug-in .
i installed the plugin to try to log users in and get redirected to an error page, i knew it wouldn’t be that easy.
So combing through the docs and limited tutorials on this matter, link below was the most comprehensive tutorial yet still hitting a wall.

i found that i need to run an oauth/token endpoint ater getting the code to exchange for a token.
i set the call up to a tee according to the pinterest docs etc. yet still getting errors.

anyone out there successfully set this up and can kindly provide some guidance?