diff --git a/AFOAuth2Manager/AFOAuth2Manager.m b/AFOAuth2Manager/AFOAuth2Manager.m
index 88d83f11..5aad312e 100644
--- a/AFOAuth2Manager/AFOAuth2Manager.m
+++ b/AFOAuth2Manager/AFOAuth2Manager.m
@@ -234,6 +234,7 @@ - (NSURLSessionTask *)authenticateUsingOAuthWithURLString:(NSString *)URLString
             if (failure) {
                 failure(AFErrorFromRFC6749Section5_2Error(responseObject));
             }
+            return;
         }
 
         NSString *refreshToken = [responseObject valueForKey:@"refresh_token"];