I’m using ideas from the WordPress plugin to provide extra features to users on my MultiSite network. I can authenticate users against Patreon and when I store the access_token and refresh_token everything works as expected.
However, when I come to refresh the token, I get an ‘invalid grant’ error message. I pass in my client id and secret, and the user’s refresh token which I stored when they first connected their account. Is there anything else I should be doing?