Problem with NBU Plugin from remote master recovery

Hi All,

I have NBU plugin enabled on my VC in site A. It works fine in restoring VM images from backup server A.

I have SLP configured that replicate to a remote master server in site B.

I have added the authentication token generated on master server in site B to the plugin and it added fine. I can browse the backups on the master server in site B but when I want to restore them to site A, I get an error on the pre-recovery checks. A red cross with the words "proxy credentials"

I did open 443 and 9445 FW ports from A to B. Anyone know why this is happening?