This error occurs when the web page (or another resource) you're trying to access is restricted, meaning you don't have permission to view it. It’s called a 403 Forbidden Error because that’s the HTTP status code used by the web server to indicate this issue.

There are typically two reasons for encountering this error. First, the web server owners may have correctly set access permissions, meaning you're not authorized to access the resource. Second, the permissions may have been incorrectly configured, preventing you from accessing the resource when you should be able to.

To resolve this, you’ll need to contact your hosting provider, as the issue appears to be related to your permissions.

You can ask them to check the server configuration, particularly the client_max_body_size (for Nginx) or LimitRequestBody (for Apache) settings? These values control the size of POST requests. Since these are server-side settings, we don’t have access to modify them directly.

If adjusting these settings doesn't resolve the issue, I recommend reviewing your site's security setup. You might try temporarily disabling the Web Application Firewall (WAF) or any other firewall that could be restricting the size of POST requests.

Setting client_max_body_size or LimitRequestBody to at least 512KB should typically be sufficient for the problematic request.