Title: Clean WP install plus plugin – 500 error
Last modified: August 31, 2016

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# Clean WP install plus plugin – 500 error

 *  Resolved [Steve Cliff](https://wordpress.org/support/users/stevecliff/)
 * (@stevecliff)
 * [10 years ago](https://wordpress.org/support/topic/clean-wp-install-plus-plugin-500-error/)
 * I’ve tested on a clean 4.5 WP install with only this plugin installed. I’ve not
   changed any parameters from default but when I click on the PDF symbol on a page
   I simply get a 500 error from the server.
 * I’m not sure where to start looking to be honest! The nginx logs show this though(
   I’ve amended some info for security reasons):
 * 2016/04/17 18:50:09 [error] 11030#0: *2681 FastCGI sent in stderr: “PHP message:
   PHP Fatal error: Call to undefined function mb_detect_encoding() in /usr/share/
   nginx/smc/wp-content
    /plugins/wp-post-to-pdf-enhanced/simplehtmldom/simple-html-
   dom.php on line 988″ while reading response header from upstream, client: x.x.
   x.x, server: smc.xxx.net, reque st: “GET /hello-world/?format=pdf HTTP/1.0”, 
   upstream: “fastcgi://unix://var/run/php-fpm/php-fpm.sock:”, host: “smc.xxx.net”,
   referrer: “[https://smc.xxx.net/&#8221](https://smc.xxx.net/&#8221);
 * Would you have any ideas why this is happening? (I see a couple of other posts
   regarding error 500 as well, although obviously I understand it’s a server error
   not actually your PHP code)
 * Thanks!
    Steve.
 * [https://wordpress.org/plugins/wp-post-to-pdf-enhanced/](https://wordpress.org/plugins/wp-post-to-pdf-enhanced/)

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

 *  Plugin Author [Lewis Rosenthal](https://wordpress.org/support/users/lewisr/)
 * (@lewisr)
 * [10 years ago](https://wordpress.org/support/topic/clean-wp-install-plus-plugin-500-error/#post-7288071)
 * Hi, Steve…
 * Your first clue is:
 * `Call to undefined function mb_detect_encoding()`
 * TCPDF (and thus, this plugin) relies on mbstring. So, make sure that the mbstring
   module is installed in PHP as well as the GD library.
 * Good luck!
 * Lewis
 *  Thread Starter [Steve Cliff](https://wordpress.org/support/users/stevecliff/)
 * (@stevecliff)
 * [10 years ago](https://wordpress.org/support/topic/clean-wp-install-plus-plugin-500-error/#post-7288075)
 * Spot on Lewis! I’m a bit new to this 🙂
    I installed mbstring and voila – I have
   a PDF!
 * Thanks – I appreciate the quick response.
 * Cheers,
    Steve.
 *  Plugin Author [Lewis Rosenthal](https://wordpress.org/support/users/lewisr/)
 * (@lewisr)
 * [10 years ago](https://wordpress.org/support/topic/clean-wp-install-plus-plugin-500-error/#post-7288153)
 * Glad I could help, Steve!
 * Now to find some time to test against WP 4.5 and push some updates…
 * Cheers
 * Lewis

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

The topic ‘Clean WP install plus plugin – 500 error’ is closed to new replies.

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## Tags

 * [500 error](https://wordpress.org/support/topic-tag/500-error/)
 * [mbstring](https://wordpress.org/support/topic-tag/mbstring/)
 * [no output](https://wordpress.org/support/topic-tag/no-output/)

 * 3 replies
 * 2 participants
 * Last reply from: [Lewis Rosenthal](https://wordpress.org/support/users/lewisr/)
 * Last activity: [10 years ago](https://wordpress.org/support/topic/clean-wp-install-plus-plugin-500-error/#post-7288153)
 * Status: resolved