diff --git a/phpseclib/File/X509.php b/phpseclib/File/X509.php
index 5286341e..74ca5ff4 100644
--- a/phpseclib/File/X509.php
+++ b/phpseclib/File/X509.php
@@ -2418,7 +2418,7 @@ class X509
         $altName = [];
 
         if (isset($subject->domains) && count($subject->domains) > 1) {
-            $altName = array_map(['X509', '_dnsName'], $subject->domains);
+            $altName = array_map(['\phpseclib\File\X509', 'dnsName'], $subject->domains);
         }
 
         if (isset($subject->ipAddresses) && count($subject->ipAddresses)) {
diff --git a/tests/Unit/File/X509/X509Test.php b/tests/Unit/File/X509/X509Test.php
index 5e64fdae..8d72b902 100644
--- a/tests/Unit/File/X509/X509Test.php
+++ b/tests/Unit/File/X509/X509Test.php
@@ -453,4 +453,22 @@ Mj93S
 
         runkit_constant_remove('FILE_X509_IGNORE_TYPE');
     }
+
+    // fixed by #1104
+    public function testMultipleDomainNames()
+    {
+        extract(RSA::createKey(512));
+
+        $subject = new X509();
+        $subject->setDomain('example.com', 'example.net');
+
+        $subject->setPublicKey($publickey);
+
+        $issuer = new X509();
+        $issuer->setPrivateKey($privatekey);
+        $issuer->setDN($subject->getDN());
+
+        $x509 = new X509();
+        $x509->sign($issuer, $subject);
+    }
 }