diff --git a/src/Ocelot/Responder/ErrorsToHttpStatusCodeMapper.cs b/src/Ocelot/Responder/ErrorsToHttpStatusCodeMapper.cs
index 61d27de0..a417f2f9 100644
--- a/src/Ocelot/Responder/ErrorsToHttpStatusCodeMapper.cs
+++ b/src/Ocelot/Responder/ErrorsToHttpStatusCodeMapper.cs
@@ -32,6 +32,11 @@ namespace Ocelot.Responder
                 return 404;
             }
 
+            if (errors.Any(e => e.Code == OcelotErrorCode.UnableToCompleteRequestError))
+            {
+                return 500;
+            }
+
             return 404;
         }
     }
diff --git a/test/Ocelot.AcceptanceTests/SslTests.cs b/test/Ocelot.AcceptanceTests/SslTests.cs
index 309bbf28..be753b46 100644
--- a/test/Ocelot.AcceptanceTests/SslTests.cs
+++ b/test/Ocelot.AcceptanceTests/SslTests.cs
@@ -92,7 +92,7 @@ namespace Ocelot.AcceptanceTests
                 .And(x => _steps.GivenThereIsAConfiguration(configuration))
                 .And(x => _steps.GivenOcelotIsRunning())
                 .When(x => _steps.WhenIGetUrlOnTheApiGateway("/"))
-                .Then(x => _steps.ThenTheStatusCodeShouldBe(HttpStatusCode.NotFound))
+                .Then(x => _steps.ThenTheStatusCodeShouldBe(HttpStatusCode.InternalServerError))
                 .BDDfy();
         }
 
diff --git a/test/Ocelot.UnitTests/Responder/ErrorsToHttpStatusCodeMapperTests.cs b/test/Ocelot.UnitTests/Responder/ErrorsToHttpStatusCodeMapperTests.cs
index 27417907..fbc17868 100644
--- a/test/Ocelot.UnitTests/Responder/ErrorsToHttpStatusCodeMapperTests.cs
+++ b/test/Ocelot.UnitTests/Responder/ErrorsToHttpStatusCodeMapperTests.cs
@@ -45,6 +45,13 @@ namespace Ocelot.UnitTests.Responder
             ShouldMapErrorToStatusCode(errorCode, HttpStatusCode.ServiceUnavailable);
         }
 
+        [Theory]
+        [InlineData(OcelotErrorCode.UnableToCompleteRequestError)]
+        public void should_return_internal_server_error(OcelotErrorCode errorCode)
+        {
+            ShouldMapErrorToStatusCode(errorCode, HttpStatusCode.InternalServerError);
+        }
+
         [Theory]
         [InlineData(OcelotErrorCode.CannotAddDataError)]
         [InlineData(OcelotErrorCode.CannotFindDataError)]
@@ -60,7 +67,6 @@ namespace Ocelot.UnitTests.Responder
         [InlineData(OcelotErrorCode.RateLimitOptionsError)]
         [InlineData(OcelotErrorCode.ServicesAreEmptyError)]
         [InlineData(OcelotErrorCode.ServicesAreNullError)]
-        [InlineData(OcelotErrorCode.UnableToCompleteRequestError)]
         [InlineData(OcelotErrorCode.UnableToCreateAuthenticationHandlerError)]
         [InlineData(OcelotErrorCode.UnableToFindDownstreamRouteError)]
         [InlineData(OcelotErrorCode.UnableToFindLoadBalancerError)]