I can't access the PC in another building.

[EricPerl]

Personally, I don't get the overall topology.

OrgA (Right):
The FW icon is OPN, right?
With 3 interfaces?
* WAN - 192.168.0.254/24
* LAN - 172.17.32.1/21
* KSPD_A - 10.62.65.254/24

OrgB (Left) has one interface KSPD_B - 10.62.70.254/24
Clarity was be improved if interfaces had different names in both orgs... We're looking at screens and it's not obvious which side they belong too.

...
Both organizations use a coordinator to communicate with each other via the KSPD channel.

What does that mean?

And then there's a machine in OrgA that's dual homed (on LAN & KSPD)???

[Shild73]

OrgA (Right):
The FW icon is OPN, right?
 With 3 interfaces?
* WAN - 192.168.0.254/24
* LAN - 172.17.32.1/21
* KSPD_A - 10.62.65.254/24

Yes. this is an OPNsense.

The WAN is used to access the Internet. KSPD is a secure network with no Internet access. To access both networks from the same computer, I use a LAN with prescribed access to services via System: Routes

interface

OrgB (Left) has one interface KSPD_B - 10.62.70.254/24
Clarity was be improved if interfaces had different names in both orgs... We're looking at screens and it's not obvious which side they belong too.

coordinator

And then there's a machine in OrgA that's dual homed (on LAN & KSPD)???

I tried to register 172.17.39.13/21 and 10.62.65.13/24 on the same interface so that 10.65.70.59 would gain access to the server.

[EricPerl]

I'm not opening that coordinator link and all info on that product seems to be in Russian anyway.
I'll assume some sort of overlay network to establish site to site connectivity. Is it essentially a VPN appliance?

I assume the loop is completed over the internet. That initial diagram is clearly missing pieces...
Do you confirm?
There's another router with internet connectivity in OrgB? OPN as well?

And please attach screenshots directly to your reply (using preview or reply, versus quick reply).
I'm not following another link in this thread.