The earliest recollection of this bug is traced back to PAN-OS 10.2.0 - July 22, 2025. This bug is fixed in PAN-OS versions 10.2.5. Certificate-based authentication for administrator accounts may be unable to log into the Panorama or firewall web interface with the following error: Bad Request - Your browser sent a request that this server could not understand Fixed an issue where certificate-based authentication for administrators were unable to log in to the Panorama or firewall web interface and received the following error message: Bad Request - Your browser sent a request that this server could not understand . For more information: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-release-notes/pan-os-10-2-0-known-and-addressed-issues/pan-os-10-2-0-known-issues https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-release-notes/pan-os-10-2-5-known-and-addressed-issues/pan-os-10-2-5-addressed-issues https://docs.paloaltonetworks.com/pan-os/11-0/pan-os-release-notes/pan-os-11-0-0-known-and-addressed-issues/pan-os-11-0-0-known-issues https://docs.paloaltonetworks.com/pan-os/11-0/pan-os-release-notes/pan-os-11-0-1-known-and-addressed-issues/pan-os-11-0-1-known-issues