Title: FastCGI: incomplete headers (0 bytes)
Last modified: January 2, 2025

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# FastCGI: incomplete headers (0 bytes)

 *  Resolved [marcelstoer](https://wordpress.org/support/users/marcelstoer/)
 * (@marcelstoer)
 * [1 year, 5 months ago](https://wordpress.org/support/topic/fastcgi-incomplete-headers-0-bytes/)
 * The host provider recently switched to PHP 8.1. I had to first increase the PHP`
   memory_limit` to 2048 to get rid off the “memory size of nnn bytes exhausted”
   errors. The page requests then didn’t fail with HTTP 500 immediately anymore 
   but only after 10+ seconds. The error log shows this.
 *     ```wp-block-code
       [Wed Jan 01 22:53:54.519569 2025] [-:error] [pid 35295:tid 38445341952] [client xx.xx.205.62:50372] FastCGI: incomplete headers (0 bytes) received from server "/var/run/hcgi/70419", referer https://frightanic.com
       ```
   
 * Disabling the WTC plugin fixes this. Re-enabling it causes the same errors again.
   Hence, the behavior is clearly traceable back to this plugin. The version installed
   is the latest 2.8.2.
 * Any ideas what I can do to fix this?
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffastcgi-incomplete-headers-0-bytes%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Contributor [Marko Vasiljevic](https://wordpress.org/support/users/vmarko/)
 * (@vmarko)
 * [1 year, 5 months ago](https://wordpress.org/support/topic/fastcgi-incomplete-headers-0-bytes/#post-18222602)
 * Hello [@marcelstoer](https://wordpress.org/support/users/marcelstoer/)
 * Thank you for reaching out and I am happy to help!
   W3 Total Cache is fully compatible
   with PHP 8.1 and the issue you are referring to is not due to the W3 Total Cache,
   if that were the case, this would be a major issue and would be reported multiple
   times by now.This being said, while the W3TC may trigger this, this is related
   to the PHP installation and the modules. This is most likely due to the idle 
   timeout setting for FastCgiServer, or you may just need to restart the PHP service
   after the upgrade.
 * Can you please check with your host what is the idle timeout setting for FastCgiServer?
 * Thanks!
 *  Thread Starter [marcelstoer](https://wordpress.org/support/users/marcelstoer/)
 * (@marcelstoer)
 * [1 year, 5 months ago](https://wordpress.org/support/topic/fastcgi-incomplete-headers-0-bytes/#post-18222780)
 * Thanks Marko!
 * “Can you please check with your host what is the idle timeout setting for FastCgiServer?”–
   Is this something I should see through `info.php`? I checked the information 
   but couldn’t find anything related to that, complete output: [https://filebin.net/kyb8x8goodulan15/frightanicdotcom_phpinfo.pdf](https://filebin.net/kyb8x8goodulan15/frightanicdotcom_phpinfo.pdf)
 *  Thread Starter [marcelstoer](https://wordpress.org/support/users/marcelstoer/)
 * (@marcelstoer)
 * [1 year, 5 months ago](https://wordpress.org/support/topic/fastcgi-incomplete-headers-0-bytes/#post-18222840)
 * I decided to activate the plugin again in order to start fiddling with its settings.
   Turns out that disabling the disk-based database cache solves this issue.

Viewing 3 replies - 1 through 3 (of 3 total)

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 * 3 replies
 * 2 participants
 * Last reply from: [marcelstoer](https://wordpress.org/support/users/marcelstoer/)
 * Last activity: [1 year, 5 months ago](https://wordpress.org/support/topic/fastcgi-incomplete-headers-0-bytes/#post-18222840)
 * Status: resolved