diff --git a/AFNetworking/AFURLConnectionOperation.m b/AFNetworking/AFURLConnectionOperation.m
index 85f2045..cfe0f9c 100644
--- a/AFNetworking/AFURLConnectionOperation.m
+++ b/AFNetworking/AFURLConnectionOperation.m
@@ -704,7 +704,15 @@ didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
     if ([request.HTTPBodyStream conformsToProtocol:@protocol(NSCopying)]) {
         return [request.HTTPBodyStream copy];
     }
-    
+
+    self.error = [NSError errorWithDomain:AFNetworkingErrorDomain code:NSURLErrorCancelled userInfo:nil];
+
+    [self.outputStream close];
+
+    [self finish];
+
+    self.connection = nil;
+
     return nil;
 }