@baris sorry for the late reply I'm based in Europe. Thank you very much, it's working great now.

Hiya, I wrote a tutorial about setting up single sign-on for NodeBB. Full disclosure, I wrote it using my employers OAuth server (FusionAuth) as the user identity provider. But the plugin and steps should work with any OAuth server. The plugin is here: https://github.com/FusionAuth/nodebb-plugin-fusionauth-oidc