Describe the problem
If I call the vouch-proxy /logout?url=${end_session_endpoint} endpoint with the okta idp end_session_endpoint url, I get a "invalid_client" error

{"errorCode":"invalid_client","errorSummary":"Invalid value for 'client_id' parameter.","errorLink":"invalid_client","errorId":"oaehsEOpVx2QZm1Q-9EBGxC7A","errorCauses":[]}

Expected behavior
If I call /logout?url=https://dev-1234.okta.com/oauth2/default/v1/logout I should be logged off from vouch-proxy and okta

Desktop (please complete the following information):

• OS: Windows 10 (2004)
• Browser Edge (Chromium based)
• Version: current

Additional context
vouch config: https://hasteb.in/imojefig.http
nginx config: https://hasteb.in/codahuva.nginx
vouch log: https://hasteb.in/adefixub.bash
nginx log: https://hasteb.in/hoveduzo.coffeescript