How might a firewall or network appliance interact with a web server to indirectly cause or mask an `error 403_3`?

While `error 403.3` specifically indicates a server-side permission issue, a firewall or network appliance could indirectly cause or mask it. If a firewall is configured to block certain HTTP methods (like PUT or POST, which are often associated with write operations) or to filter specific types of content, it might prevent a client's write request from even reaching the web server correctly. This could result in a different error or an incomplete request that the server then interprets as a forbidden action, potentially leading to a 403.3 if the partial request still triggers an internal write attempt without proper authorization, or simply confusing the client about the true cause of the access denial.