diff --git a/src/Libraries/Thinktecture.IdentityServer.Protocols/Shared/AuthenticationHelper.cs b/src/Libraries/Thinktecture.IdentityServer.Protocols/Shared/AuthenticationHelper.cs
index cb8349c9..62c3fd30 100644
--- a/src/Libraries/Thinktecture.IdentityServer.Protocols/Shared/AuthenticationHelper.cs
+++ b/src/Libraries/Thinktecture.IdentityServer.Protocols/Shared/AuthenticationHelper.cs
@@ -280,7 +280,7 @@ public RelyingParty GetRelyingPartyDetailsFromReturnUrl(string returnUrl)
             var url = HttpUtility.UrlDecode(returnUrl);
             Uri uri;
 
-            if (Uri.TryCreate(url, UriKind.RelativeOrAbsolute, out uri))
+            if (Uri.TryCreate("http://foo.com" + url, UriKind.Absolute, out uri))
             {
                 WSFederationMessage message;