Signout Request Causing Errors

Question

I am using ADFS 2016 for OAuth2/OIDC. In some cases I see the following error (551) in the event viewer:

An error occurred during processing of an OAuth logout request. 
Path: /adfs/oauth2/logout?post_logout_redirect_uri=*******&id_token_hint=*****
Additional Data 

Exception details: 
System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at Microsoft.IdentityServer.Web.Protocols.OAuth.OAuthAuthorization.OAuthSignoutProtocolHandler.GetLogoutUrisFromSession(OAuthSessionInfo sessionInfo, String issuer)
   at Microsoft.IdentityServer.Web.Protocols.OAuth.OAuthAuthorization.OAuthSignoutProtocolHandler.ProcessSignout(ProtocolContext context, List`1 iFrameSignoutUris, Boolean isPartial)

Any idea what could be the cause of this error?

the following exception occurs with your module as identical properties `An item with the same key has already been added.` — djsly, May 14 '20 at 13:34

score 1 · Answer 1 · answered May 14 '20 at 13:39

Based on those two issues, it seems that this Event is mostly related to an incorrect passive request

https://answers.microsoft.com/en-us/msoffice/forum/all/issues-with-domain-owa/4877a550-1d25-4669-bee1-59d9b0993826

there is also another case which could be related to not using the right protocol.

https://stackoverflow.com/a/37395400/2690525

I would review your request to ensure that nothing obvious with them could be triggering those Events.

Signout Request Causing Errors

1 Answers1