I wonder if there is a communication issue between your server and the box, I presume a) they are on the same router, b) not with one running vpn, c) no firewall of any sort between them etc.
This may or may not be relevant, but is remote access enabled, for the server, in Settings/Server/Remote Access, and it might help to enter the box ip address in "List of IP addresses and networks that are allowed without auth" within Settings/Server/Network
Cheers!