Just looked at the sample on Github, and references are out of date.
Updating the references breaks the sample.
Would it be possible to get a working sample with the latest versions of your dll and identitymodel 4?
okta-hosted-login is the one i’d like
Identity Model 4.0 and Okta Asp.Net 1.4.0
To get more visibility for your question, I’d suggest you post it as an issue in the samples repository on GitHub. That way, you’ll be in contact with the maintainers and will be notified when it’s fixed.