Additional uncaught exception thrown while handling exception.

Original

PDOException: SQLSTATE[HY000]: General error: 2013 Lost connection to MySQL server during query in drupal_is_denied() (line 2193 of /app/arduino.vn/includes/bootstrap.inc).

Additional

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT 1 AS expression FROM {variable} variable WHERE ( (name = :db_condition_placeholder_0) ); Array ( [:db_condition_placeholder_0] => cdn_css_cache_files_http ) in variable_set() (line 1245 of /app/arduino.vn/includes/bootstrap.inc).