Error: Failed to upload image Device msg:'Failed to download PanOS_xx. Download error: HTTP response code said error.'

• While trying to upload content updates/PanOS image from Panorama to managed firewall from Panorama-->Device Deployment option, following error is seen

Failed to upload image Device msg:'Failed to download PanOS_xx. Download error: HTTP response code said error.'

• Panorama in HA pair

• When deploying content updates to managed devices when Panorama is in a high availability (HA) configuration, Panorama balances the content update jobs between the HA peers to decrease the load on each Panorama.
• In the event that an HA peer becomes unreachable during the content update, the content update jobs fail for the managed devices to which the down HA peer would normally push the content updates. This occurs for both scheduled and manual content updates.

1. Log in to the Panorama CLI and disable load balancing for content updates

admin> set dlsrvr distribute no

2. Upload and Install the content update/PanOS image from Panorama using device deployment option
3. Enable back load balancing for content updates

admin> set dlsrvr distribute yes

• Reference: https://docs.paloaltonetworks.com/panorama/9-1/panorama-admin/troubleshooting/complete-content-update-when-panorama-ha-peer-is-down