Pings do not go between the guest and the host in network bridge mode (Win10 host, Win2003 guest). How to decide?

Question

virtual box

Situation host - win10, guest - win2003(server).
The network in VirtualBox (Version 5.0.4) is configured in the "Network bridge" mode. The
host is connected to the router.
A couple more computers are connected to the router.
So, from all computers, except for the host and guest, pings go both to the host and to the guest. But between the host and the guest pings do not go!
Everything is pinged from the host except the guest.
Everything except the host is pinged from the guest.
Can anyone come across how to overcome this problem?
Or is it possible to test such a scheme at your stand.