You get a WordPress error that says, “HTTP Loopback Connections Disabled.”
Most of the web sites had pointless or ineffective solutions. Some said to add define('ALTERNATE_WP_CRON', true); to wp-config.php, which was completely irrelevant, uneffective and annoying. Others first defined what a loopback was (thanks, Sherlock) and suggested that I associate every domain with 127.0.0.1 in /etc/hosts, which:
- This is neither an issue nor required on my other cPanel instance.
- That is rather ridiculous to do for each domain on a shared server setup.
What Worked For Me
It turns out that allow_url_fopen was disabled on this (new) instance. Once I enabled that (which is on by default in PHP), the errors went away. In WHM:
- Go to Software > MultiPHP INI Editor
- Enable (if disabled) allow_url_fopen, apply and restart Apache.
This may not work for you, but it fixed my problems instantly. I wasn’t aware that it was disabled, and the error message(s) were obscure. I just thought that I would make a post in case someone stumbles across it and it’s helpful.
For end-users, you can also try adding this to wp-config.php and see if it works for you:
ini_set( 'allow_url_fopen', 1 );