HTTP Loopback Connections are not enabled on this server.

xMax

The Error : HTTP Loopback Connections are not enabled on this server. When PHP tries to connect back to the site at the URL https://mydomain.com/wp-admin/admin-ajax.php , it gets the error Response code: 500. There may be a problem with the server configuration (eg local DNS problems, mod_security, etc) preventing connections from working properly.

This is not a problem with my hosting povider, because this error only shows up when I installed aaPanel.

aaPanel_Jose

xMax
Please enter the following command in the ssh terminal to check
Check if the 80 port listening
netstat -ntulp|grep 80

Check if the firewall released the 80 port
Centos:
firewall-cmd --list-all |grep 80
Ubuntu/Debian
ufw status|grep 80

maverick

Yes aaPanel has that problem. If you use any other panel, or if you configure the webserver from scratch by yourself, those problems will disappear.

The developers are completely oblivious about the source of that problem so they always say there's no problem.