e107 uses various security methods to keep your site protected from abuse. However, some server configurations are incompatible with these methods, usually due to these servers employing similar security methods.
In order to disable only the parts which may cause you problems, we recommend you add the following code on a new line in your e107_config.php file, and see if that helps. If not, please submit an Issue on Github - we'll do our best to find a solution for you.
define('e_SECURITY_LEVEL', 0);
