Disabling mod_sec

If some requests from MapSVG to the server are failing without any obvious reason, it could be caused by the mod_sec Apache's module that blocks suspicious requests.

What you can try to do first is disable mod_sec entirely and see if that helps. If it does, check the mod_sec logs and find the reason of the blockage. When you find the reason, you can change mod_sec setting to prevent the blockage.

How to disable mod_sec: add the following lines to the .htaccess file in your WordPress root folder:

<IfModule mod_security.c>
    SecFilterEngine Off
    SecFilterScanPOST Off
</IfModule>    

The method above may not work though. If you have a control panel on your server, it may be possible to disable mod_sec there. If you don't have a control panel, try to google how to do disable mod_sec on your server OS.

If you have enough experience, you can try to disable the following mod_sec rules: 340155, 380023, 341155