diff -urN ../z-push-2.6.2+0.orig/src/backend/searchldap/searchldap.php ./src/backend/searchldap/searchldap.php
--- ../z-push-2.6.2+0.orig/src/backend/searchldap/searchldap.php	2021-02-04 03:38:38.000000000 +0200
+++ ./src/backend/searchldap/searchldap.php	2021-09-10 22:49:29.901293000 +0300
@@ -47,6 +47,9 @@
         // Connect
         if (defined('LDAP_SERVER_URI')) {
             $this->connection = @ldap_connect(LDAP_SERVER_URI);
+            if (!is_resource($this->connection)) {
+                throw new StatusException("BackendSearchLDAP(): Incorrect LDAP_SERVER_URI '" . LDAP_SERVER_URI . "'. Search aborted.", SYNC_SEARCHSTATUS_STORE_SERVERERROR, null, LOGLEVEL_FATAL);
+            }
             @ldap_set_option($this->connection, LDAP_OPT_PROTOCOL_VERSION, 3);
         }
         else {