Title: An unknown error has occured E01
Last modified: April 7, 2017

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# An unknown error has occured E01

 *  [stuartcusack](https://wordpress.org/support/users/stuartcusack83/)
 * (@stuartcusack83)
 * [9 years, 2 months ago](https://wordpress.org/support/topic/an-unknown-error-has-occured-e01/)
 * About 20 seconds after submitting a review an error is returned via a JS alert,
   even though the submission is successful and the review enters the database.
 * The error is as follows:
    An unknown error has occured E01
 * In the chrome developers console I can see:
    504 Gateway Time-out Failed to load
   resource: the server responded with a status of 504 () Failed to load resource:
   the server responded with a status of 502 ()
 * In the nginx logs on my server I can see:
    2017/04/05 11:49:56 [error] 4624#4624:*
   1538 upstream timed out (110: Connection timed out) while reading response header
   from upstream, client: 79.xxx.xxx.xxx, server: mydomain.ie, request: “POST /wp-
   admin/admin-ajax.php?action=wpcr3-ajax HTTP/2.0”, upstream: “fastcgi://unix:/
   var/run/php/php7.1-fpm.sock”, host: “mydomain.ie”, referrer: “[https://mydomain.ie/testimonials&#8221](https://mydomain.ie/testimonials&#8221);
 * It is a PHP 7.1 server and everything else runs fine.
 * Any ideas??
 * Thank you.
    -  This topic was modified 9 years, 2 months ago by [stuartcusack](https://wordpress.org/support/users/stuartcusack83/).

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 * 0 replies
 * 1 participant
 * Last reply from: [stuartcusack](https://wordpress.org/support/users/stuartcusack83/)
 * Last activity: [9 years, 2 months ago](https://wordpress.org/support/topic/an-unknown-error-has-occured-e01/)
 * Status: not resolved