Due to WordPress background heartbeat, you may run into connection issue or 403 access denied message to your webserver if there is a (Per IP Connection limit) set for the web server
To combat this, you can disable or change the heartbeat rate for your WordPress.
- Download, install and activate the Heartbeat Control plugin for your WP
- Once activated, goto Tools -> Heartbeat Control to open the plugin
- Now you can adjust the interval or the location which the heartbeat is used