[Bitrix\Main\DB\ConnectionException] 
Mysql connect error [localhost, 127.0.0.1]: Too many connections (400)
/home/bitrix/www/bitrix/modules/main/lib/db/mysqlconnection.php:50
#0: Bitrix\Main\DB\MysqlConnection->connectInternal()
	/home/bitrix/www/bitrix/modules/main/lib/db/mysqlconnection.php:103
#1: Bitrix\Main\DB\MysqlConnection->queryInternal(string, NULL, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:330
#2: Bitrix\Main\DB\Connection->query(string, NULL, integer, integer)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:358
#3: Bitrix\Main\DB\Connection->queryScalar(string)
	/home/bitrix/www/bitrix/modules/security/lib/session.php:115
#4: Bitrix\Security\SessionTable::lock(string, integer)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_db.php:52
#5: CSecuritySessionDB::read(string)
	
#6: session_start()
	/home/bitrix/www/bitrix/modules/main/include.php:281
#7: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#8: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#9: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#10: require(string)
	/home/bitrix/www/catalog/index.php:2
#11: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#12: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2

Fatal error: Uncaught exception 'Bitrix\Main\DB\ConnectionException' with message 'Mysql connect error [localhost, 127.0.0.1]: Too many connections' in /home/bitrix/www/bitrix/modules/main/lib/db/mysqlconnection.php:50 Stack trace: #0 /home/bitrix/www/bitrix/modules/main/lib/db/mysqlcommonconnection.php(130): Bitrix\Main\DB\MysqlConnection->connectInternal() #1 /home/bitrix/www/bitrix/modules/main/lib/db/connection.php(716): Bitrix\Main\DB\MysqlCommonConnection->getTableFields('b_sec_session') #2 /home/bitrix/www/bitrix/modules/main/lib/db/sqlhelper.php(387): Bitrix\Main\DB\Connection->getTableField('b_sec_session', 'SESSION_ID') #3 /home/bitrix/www/bitrix/modules/main/lib/orm/data/datamanager.php(1190): Bitrix\Main\DB\SqlHelper->prepareAssignment('b_sec_session', 'SESSION_ID', 'q4YQszXnOjFgDUG...') #4 /home/bitrix/www/bitrix/modules/security/classes/general/session_db.php(92): Bitrix\Main\ORM\Data\DataManager::delete('q4YQszXnOjFgDUG...') #5 [internal function]: CSecuritySessionDB::write('q4YQszXnOjFgDUG...', '') #6 [int in /home/bitrix/www/bitrix/modules/main/lib/db/mysqlconnection.php on line 50