The 403: Forbiddenerror indicates that the HTTPS server on the Secure Firewall Threat Defense (FTD) device is not properly configured or enabled, preventing access to the requested PCAP file. To resolve this, the engineer must enable the HTTPS service in the device platform policy applied to the FTD device in Cisco Secure Firewall Management Center (FMC). This allows the FTD to serve HTTPS requests, including access to PCAP files.