diff --git a/apps/user_ldap/lib/Connection.php b/apps/user_ldap/lib/Connection.php
index 788344b4e7d03..69e028830fa52 100644
--- a/apps/user_ldap/lib/Connection.php
+++ b/apps/user_ldap/lib/Connection.php
@@ -438,7 +438,7 @@ private function doSoftValidation() {
 
 		$backupPort = (int)$this->configuration->ldapBackupPort;
 		if ($backupPort <= 0) {
-			$this->configuration->backupPort = $this->configuration->ldapPort;
+			$this->configuration->ldapBackupPort = $this->configuration->ldapPort;
 		}
 
 		//make sure empty search attributes are saved as simple, empty array