Patreon login fails - Authentication failure! invalid_credentials:

I have a self-hosted Discourse site which uses Patreon for authentication. It has been working for one month, but now I am getting the following error when new users try to login:

(patreon) Authentication failure! invalid_credentials: OAuth2::Error, <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>405 Method Not Allowed</title>

It is exactly 30 days since I set up the integration between Patreon and Discourse. My feeling is that the problem has something to do with an expired token.

I checked the API keys and they were fine. (It had been working up until yesterday.) I tried creating a new Client on Patreon, and updated the API keys within Discourse, but this doesn’t seem to have helped.

I would really appreciate any help.

It is an issue from Patreon side and they resolved it now.