see #808 - db_log expects 3 strings ... make sure we do not pass in a null

model/DkimHandler.php

@@ -87,7 +87,7 @@ class DkimHandler extends PFAHandler
 
         db_delete($this->db_table, $this->id_field, $this->id);
 
-        db_log($this->result['domain_name'], 'delete_dkim_entry', $this->result['label']);
+        db_log($this->result['domain_name'], 'delete_dkim_entry', $this->result['description'] ?? '');
         $this->infomsg[] = Config::Lang_f('pDelete_delete_success', $this->result['label']);
         return true;
     }