When setting these options consider the following:

• How long is your average request?
• What is the maximum number of simultaneous visitors the site(s) get?
• How much memory on average does each child process consume?

• sudo grep max_children /var/log/php?.?-fpm.log.1 /var/log/php?.?-fpm.log

This error is usually caused by AJAX calls, and is due to there being too much data in the request for Nginx to process with its current settings.

1. Create ~/.config/valet/nginx/all.conf with the following:

    proxy_buffer_size 4096k;
    proxy_buffers 128 4096k;
    proxy_busy_buffers_size 4096k;