[RuntimeException] 
Could not start session because headers have already been sent. "/home/i/itssauna/its-sauna.ru/public_html/catalog/index.php":10. (0)
/home/i/itssauna/its-sauna.ru/public_html/bitrix/modules/main/lib/session/session.php:124
#0: Bitrix\Main\Session\Session->start()
	/home/i/itssauna/its-sauna.ru/public_html/bitrix/modules/main/lib/session/kernelsessionproxy.php:52
#1: Bitrix\Main\Session\KernelSessionProxy->start()
	/home/i/itssauna/its-sauna.ru/public_html/bitrix/modules/main/include.php:299
#2: require_once(string)
	/home/i/itssauna/its-sauna.ru/public_html/bitrix/modules/main/include/prolog_before.php:14
#3: require(string)
	/home/i/itssauna/its-sauna.ru/public_html/catalog/index.php:13
#4: include_once(string)
	/home/i/itssauna/its-sauna.ru/public_html/bitrix/modules/main/include/urlrewrite.php:159
#5: include_once(string)
	/home/i/itssauna/its-sauna.ru/public_html/bitrix/urlrewrite.php:2