[RuntimeException] 
Could not start session because headers have already been sent. "/home/b4922/velikan-43.ru/WWW/ajax/marketing.php":2. (0)
/home/b4922/velikan-43.ru/WWW/bitrix/modules/main/lib/session/session.php:144
#0: Bitrix\Main\Session\Session->start()
	/home/b4922/velikan-43.ru/WWW/bitrix/modules/main/lib/session/kernelsessionproxy.php:47
#1: Bitrix\Main\Session\KernelSessionProxy->start()
	/home/b4922/velikan-43.ru/WWW/bitrix/modules/main/include.php:168
#2: require_once(string)
	/home/b4922/velikan-43.ru/WWW/bitrix/modules/main/include/prolog_before.php:19
#3: require(string)
	/home/b4922/velikan-43.ru/WWW/ajax/marketing.php:3
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