DB Error: MySQL server has gone away

Stack Trace:

File: /var/www/html/classes/article/AuthorDAO.inc.php line 63
Function: DAO->retrieve("SELECT DISTINCT aa.submission_id FROM authors aa LEFT...", Array(6))

File: /var/www/html/pages/search/SearchHandler.inc.php line 180
Function: AuthorDAO->getPublishedArticlesForAuthor(Null, "Legis Ocktaviana", Null, "Saputri", "Universitas Muhammadiyah Mataram", Null)

File: (unknown) line (unknown)
Function: SearchHandler->authors(Array(1), Object(Request))

File: /var/www/html/lib/pkp/classes/core/PKPRouter.inc.php line 362
Function: call_user_func(Array(2), Array(1), Object(Request))

File: /var/www/html/lib/pkp/classes/core/PKPPageRouter.inc.php line 220
Function: PKPRouter->_authorizeInitializeAndCallRequest(Array(2), Object(Request), Array(1), False)

File: /var/www/html/lib/pkp/classes/core/Dispatcher.inc.php line 134
Function: PKPPageRouter->route(Object(Request))

File: /var/www/html/lib/pkp/classes/core/PKPApplication.inc.php line 178
Function: Dispatcher->dispatch(Object(Request))

File: /var/www/html/index.php line 69
Function: PKPApplication->execute()

DB Error: MySQL server has gone away

Stack Trace:

File: /var/www/html/lib/pkp/classes/session/SessionDAO.inc.php line 119
Function: DAO->update("UPDATE sessions SET user_id = ?, ip_address = ?, ...", Array(9))

File: /var/www/html/lib/pkp/classes/session/SessionManager.inc.php line 186
Function: SessionDAO->updateObject(Object(Session))

File: (unknown) line (unknown)
Function: SessionManager->write("b4itvaqqo3kjnf5pkkugv1c6g3", "")

File: (unknown) line (unknown)
Function: session_write_close()