ADFS - An item with the same key has already been added at Microsoft.IdentityServer.Web.HomeRealmModule.FindApplicableRealms

Hi,

I'm struggling to understand what happens here.

I configured ADFS on Windows Server 2012 R2. Everything worked. when I tried to access adfs/ls/idpInitiatedSignOn (removed full link since I was not able to submit question) I got an error as:

System.ArgumentException: An item with the same key has already been added. at
System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean
add) at
Microsoft.IdentityServer.Web.HomeRealmModule.FindApplicableRealms(ProtocolContext
context, Boolean needsIDPInstance) at
Microsoft.IdentityServer.Web.HomeRealmModule.DiscoverHomeRealm(PassiveProtocolHandler
pHandler, ProtocolContext context) at
Microsoft.IdentityServer.Web.PassiveProtocolListener.GetAuthenticationMethods(PassiveProtocolHandler
protocolHandler, ProtocolContext protocolContext) at
Microsoft.IdentityServer.Web.PassiveProtocolListener.OnGetContext(WrappedHttpListenerContext
context)

Searched through MSDN, google and all others that faced this issue did not receive an answer.

Can anyone please help its urgent. Thanks