Warning: fopen(/var/log/php/exceptions.log): Failed to open stream: No such file or directory in /home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/lib/diag/filelogger.php on line 35

Warning: fopen(/var/log/php/exceptions.log): Failed to open stream: No such file or directory in /home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/lib/diag/filelogger.php on line 35
<pre>[RuntimeException] 
Could not start session because headers have already been sent. &quot;/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/lib/diag/filelogger.php&quot;:35. (0)
/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/lib/session/session.php:143
#0: Bitrix\Main\Session\Session-&gt;start()
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/lib/session/kernelsessionproxy.php:47
#1: Bitrix\Main\Session\KernelSessionProxy-&gt;start()
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/include.php:176
#2: require_once(string)
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/include/prolog_before.php:19
#3: require_once(string)
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/modules/main/include/prolog.php:10
#4: require_once(string)
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/header.php:1
#5: require_once(string)
	/home/t/ttechnol/pi-on.pro/public_html/404.php:7
#6: include_once(string)
	/home/t/ttechnol/pi-on.pro/public_html/bitrix/urlrewrite.php:4
----------
</pre>