The error 48,0,0 indicates you did not have a default netpool assigned. You need to add in a default netpool.

The command to add in a default netpool at virtual site level via the CLI:
vpn netpool default "netpool_name"

Steps to add in a default netpool at virtual site level via the webui:
Under Access methods -> click on L3vpn
Under Netpools -> click on Set As default