DB Error: MySQL server has gone away

Stack Trace:

File: /var/www/html/classes/subscription/InstitutionalSubscriptionDAO.inc.php line 718
Function: DAO->retrieve(" SELECT iss.subscription_id FROM institutional_subs...", Array(3))

File: /var/www/html/classes/issue/IssueAction.inc.php line 160
Function: InstitutionalSubscriptionDAO->isValidInstitutionalSubscription("172.16.254.20", "172.16.254.20", "5")

File: /var/www/html/pages/article/ArticleHandler.inc.php line 454
Function: IssueAction->subscribedDomain(Object(Journal), "347", "5244")

File: /var/www/html/pages/article/ArticleHandler.inc.php line 55
Function: ArticleHandler->validate(Object(Request), "5244", 0)

File: (unknown) line (unknown)
Function: ArticleHandler->view(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("j5bs25htj9j6nc3u4k0surodu1", "")

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