Get SSH to the VxRail Manager as mystic user and elevate to root user.
su root
Run the following command:
wld01-vxmgr:/home/mystic # curl --unix-socket /var/lib/vxrail/nginx/socket/nginx.sock -X GET "http://localhost/rest/vxm/internal/lockbox/v1/credentials?lockbox_name=SYSTEM&credential_names=management_account_vc"|jqThis should then list the service account password.