diff --git a/lib/cocoa/src/transport/THTTPClient.m b/lib/cocoa/src/transport/THTTPClient.m
index 6711a0a..1eaa859 100644
--- a/lib/cocoa/src/transport/THTTPClient.m
+++ b/lib/cocoa/src/transport/THTTPClient.m
@@ -140,7 +140,7 @@
   if (![response isKindOfClass: [NSHTTPURLResponse class]]) {
     @throw [TTransportException exceptionWithName: @"TTransportException"
                                            reason: [NSString stringWithFormat: @"Unexpected NSURLResponse type: %@",
-                                                    [response className]]];
+                                                    NSStringFromClass([response class])]];
   }
 
   NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *) response;