UnsupportedApiVersion The HTTP Resource That Matches The Request URI Does Not Support HTTP Method POST

Everyday at first login Error Message {"error "code":"UnsupportedApiVersion message: The HTTP resource that matches the request URI "https://FQDN/signinsystemopenidconnect does not support HTTP method POST","innerError":null}} . After a browser refresh (F5) it is possible to access without any issues.

Issue Description: After upgrading the Orchestrator instance to latest supported version, the users machines had a first login issue that could be resolved for the moment by refreshing the browser page.



Steps followed to understand the issue:

Activated Failed Request Tracing rule and found that the 405 response that we also found in the HAR trace was related to the module AspNetCoreModuleV2 with the notification that EXECUTE_REQUEST_HANDLER does not allows the connection.

Verified the Orchestrator and IIS but there were no connectivity or configuration mismatches.


  • It is found that the Orchestrator URL is saved into the bookmark with the auth tokens from an older instance.



  • The URL should contain only the FQDN of the Orchestrator machine like below.


  • After changing the URL from the bookmark and removing the unnecessary tokens \ clientid, the Orchestrator is accessible without any issues and the error was no longer generated.