where could be problem when some time connection is not
established after server restart, but some time it is OK.
(I waited whole day)

Filters are opened for all IP from and to both servers in
VPN. Both servers are BM3.7 SP2, NDS Version 10350.19 March 18, 2003
Slave server contain RW replica of the container where the server
(I tried also Master replica) here are also licenses for NW6 and BM3.7

Master server is in different replica which is not on slave server.

Both servers are on same subnet.

Packet capture shows only IP 57 communication from Master to Slave

Any suggestion?