I am one of our admins and also a software engineer. I think the issue I am having has to do with cookies and the “state” between discourse and Canvas not matching.
This is the error I am getting in Discourse logs
(lti) Authentication failure! state_mismatch: StandardError, State parameter did not match the session
I think that error is getting thrown from here: discourse-lti/lib/discourse_lti/lti_omniauth_strategy.rb at main · discourse/discourse-lti · GitHub
Any ideas or things i can look into to help debug this? On this page in the Canvas Docs: Overview of an LTI Launch <a name="launch-overview"></a> - Canvas LMS REST API Documentation
There is a Launching without Cookies section that I think is relevant here. But I am not 100% sure. Any help or insights would be greatly appreciated.