Wordpress users sent back to wp-login page

My users are getting an issue where they are clicking on login via Patreon button at the Wordpress login page and then approving auth via patreon accept/deny etc and then get redirected back to the Wordpress login page, asking them to login again.

I have disabled all caching via Nginx, Apache and Cloudflare. The API connection has been refreshed and is working etc.

Im not sure what to look for to fix this, any ideas please?

:raised_hands: anyone have any ideas of the cause???