A new issue has popped up on some WordPress sites. When you try to edit a template or file from the WordPress admin, you will see a 406 Not Acceptable error.
This is often caused if the host has installed ModSecurity which is an application firewall.
Lucky for us, we can often bypass this in .htaccess.
Open .htaccess and place the following at the top of the file;
Save the file and try again.
If this doesn’t work, you will need to contact the web host.