Cannot connect to 2008r2 from Windows 10

SMBv1 should be disabled.  Did you enable SMBv1 on Windows 10?  If so, disable it and try again.

Try by starting “Function Discovery Provider Host” and “Function Discovery Resource Publication” services.

On server or client?

Connection works from different network.

Could you clarify this part of the comment?

Did your connection failures occur when you used server name, IP address, or both? I would try to see whether you can verify that Windows 10 is trying to at least negotiate SMB v 2.1 with your server.

I started “Function Discovery Provider Host” and “Function Discovery Resource Publication” services on the Windows 10 machine.

They are in different office buildings.

Are you able to browse the server by IP from the same network? I assume that the workstations on each network are using the same update of Windows 10, correct? Is NetBIOS over TCP/IP enabled on any of the systems? (Compare one that worked to one that didn't)

I can ping IP of server from both computers. Both are using the same version/ revision of windows. Both are using default NetBios settings.

Connection failure is occurring both of the IP and the server name. How can I determine whether Windows 10 machine is trying to transmit / communicate via SMB V2

How to Detect, Enable, Disable SMBv1 from Microsoft

https://support.microsoft.com/en-ca/help/2696547/how-to-detect-enable-and-disable-smbv1-smbv2-and-smbv3-in-windows-and

I viewed the article. Verified that SMBv2 is running on the Windows 10 that is having trouble.

Here is a TechNet article that goes into a lot of detail (Windows 10 isn't listed, but this same stuff still basically applies):
https://blogs.technet.microsoft.com/josebda/2010/10/26/what-version-of-smb2-am-i-using-on-my-windows-file-server/

You might look into the negotiations.

But also, I recommend trying to look into the connections at the firewall level. Try disabling the firewall on the server, and see if anything changes.

On the problem Windows 10 machine, run DISM and please let us know

From an admin command prompt, dism.exe /online /cleanup-image /restorehealth .  Restart and test.

If you still have issues, you may need to run a Windows 10 Repair Install from the Microsoft Media Creation Link.

Firewall on the server has been disabled but the problem persist.

Enable the firewall again, but you might want to enable logging for Windows Firewall. You will want to pay the most attention to ports 139 and 445.

Do the Basic Tests, first. On the command line of win10, launch:
Telnet servername 445
if Telnet is not installed, you'll Need to install it as a Windows feature, first.
If the smb port 445 is reachable, the command Shell would go black. Let us know what happens.

Screen went black.

Ok, that's fine.
And what excatly is the error that you see when trying to Access \\servername?

Windows cannot access \\xxxxxxxxx \xxxxxx

Check spelling of the name.........

Error code : 0x80004005
Unspecified Error

Can ping name and IP.

That is occurring on all machines at a particular location.

And only on this server, which is on a different subnet. They connect to servers on the same subnet without issues.

Is your Server all up to date?  You may need to update BIOS and Chipset (Use great care) to get the remaining Windows Updates.

You need to try with a clean 2008 R2 (just windows, no additional software), first on the same subnet (will work), then on the other subnet (shouldn't be a problem, if routing is configured). Share the results.

Any chance that some of the traffic is getting filtered between the subnets?

Any updates?

What ended up being the solution?