diff --git a/AFNetworking/AFSecurityPolicy.m b/AFNetworking/AFSecurityPolicy.m
index 159e316..4d7443b 100644
--- a/AFNetworking/AFSecurityPolicy.m
+++ b/AFNetworking/AFSecurityPolicy.m
@@ -171,7 +171,7 @@ static NSArray * AFPublicKeyTrustChainForServerTrust(SecTrustRef serverTrust) {
         }
         self.pinnedPublicKeys = [NSArray arrayWithArray:mutablePinnedPublicKeys];
     } else {
-        self.pinnedCertificates = nil;
+        self.pinnedPublicKeys = nil;
     }
 }