Connecting with Win 2008r2 to Mac OS

Solution 1:

The Server 2008 machine is running SMBv1 which is the main cause of connection issues with newer machines not using SMBv1 (SMBv2 or greater instead).

Server 2008 SMB version

Server 2008 is well out of support and no upgrades for it.

There is a registry key to check version, but I do not see any way to upgrade the SMB version.

I do not recommend it but you can consider downgrading SMB on newer machines. This is a security risk and I do not recommend it.

You could consider a good strong Windows 10 machine as a "Server" for testing purposes.