[RuntimeException] 
Could not start session because headers have already been sent. "/home/bitrix/ext_www/slavia.by/promo/verum/index.php":169. (0)
/home/bitrix/ext_www/slavia.by/bitrix/modules/main/lib/session/session.php:133
#0: Bitrix\Main\Session\Session->start()
	/home/bitrix/ext_www/slavia.by/bitrix/modules/main/lib/session/kernelsessionproxy.php:42
#1: Bitrix\Main\Session\KernelSessionProxy->start()
	/home/bitrix/ext_www/slavia.by/bitrix/modules/main/include.php:166
#2: require_once(string)
	/home/bitrix/ext_www/slavia.by/bitrix/modules/main/include/prolog_before.php:14
#3: require_once(string)
	/home/bitrix/ext_www/slavia.by/local/include/ajax_shops.php:12
#4: require(string)
	/home/bitrix/ext_www/slavia.by/promo/verum/index.php:171