Title: PHP warnings choking nginx
Last modified: May 10, 2019

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# PHP warnings choking nginx

 *  Resolved [velocity4](https://wordpress.org/support/users/velocity4/)
 * (@velocity4)
 * [7 years, 1 month ago](https://wordpress.org/support/topic/php-warnings-choking-nginx/)
 * From what I can tell in our logs, when a woocommerce customer tries to add an
   item to their cart or check out under certain conditions, the following warning
   `
   PHP message: PHP Warning: Use of undefined constant MB_CASE_UPPER - assumed '
   MB_CASE_UPPER' (this will throw an Error in a future version of PHP) in /var/
   www/boschmixers.com/htdocs/wp-content/plugins/mailpoet/vendor/symfony/polyfill-
   mbstring/Mbstring.php on line 533` is raised so many times that it then induces`
   2019/05/10 21:28:44 [error] 26467#26467: *1396248 upstream sent too big header
   while reading response header from upstream, client: 209.33.198.47, server: boschmixers.
   com, request: "GET /?add-to-cart=48 HTTP/1.1", upstream: "fastcgi://unix:/var/
   run/php/php7.2-fpm.sock:", host: "www.boschmixers.com", referrer: "https://www.
   boschmixers.com/"` For now we’ve disabled the mailpoet plugin.

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Plugin Author [MailPoet](https://wordpress.org/support/users/mailpoet/)
 * (@mailpoet)
 * [7 years, 1 month ago](https://wordpress.org/support/topic/php-warnings-choking-nginx/#post-11612458)
 * Hey [@velocity4](https://wordpress.org/support/users/velocity4/),
 * could you please contact us directly from inside the plugin ([https://www.mailpoet.com/support/](https://www.mailpoet.com/support/))?
   We can’t replicate your issue and we’ll need access to your WordPress in order
   to further investigate.
 * Thanks!
 *  [stephaned](https://wordpress.org/support/users/stephaned/)
 * (@stephaned)
 * [7 years, 1 month ago](https://wordpress.org/support/topic/php-warnings-choking-nginx/#post-11612469)
 * I have open a ticket also on the support mailpoet

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘PHP warnings choking nginx’ is closed to new replies.

 * ![](https://ps.w.org/mailpoet/assets/icon-256x256.png?rev=3284564)
 * [MailPoet - Newsletters, Email Marketing, and Automation](https://wordpress.org/plugins/mailpoet/)
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 * 2 replies
 * 3 participants
 * Last reply from: [stephaned](https://wordpress.org/support/users/stephaned/)
 * Last activity: [7 years, 1 month ago](https://wordpress.org/support/topic/php-warnings-choking-nginx/#post-11612469)
 * Status: resolved