diff --git a/lib/classes/Swift/Signers/DKIMSigner.php b/lib/classes/Swift/Signers/DKIMSigner.php
index 2000b4736..f2a25149f 100644
--- a/lib/classes/Swift/Signers/DKIMSigner.php
+++ b/lib/classes/Swift/Signers/DKIMSigner.php
@@ -682,7 +682,7 @@ private function _getEncryptedHash()
         if (!$pkeyId) {
             throw new Swift_SwiftException('Unable to load DKIM Private Key ['.openssl_error_string().']');
         }
-        if (openssl_sign($this->_headerCanonData, $signature, $this->_privateKey, $algorithm)) {
+        if (openssl_sign($this->_headerCanonData, $signature, $pkeyId, $algorithm)) {
             return $signature;
         }
         throw new Swift_SwiftException('Unable to sign DKIM Hash ['.openssl_error_string().']');