Connecting Macbook Pro to Server via Ethernet

Trying to focus on the main issue without repeating what others have mentioned:

1. You can "see" the main server, so it is offering a connection over the network and you are getting that offer (probably SMB over Bonjour/mDNS);
2. When you try and connect, you get the error referencing the version of the server not being supported. This likely means one (or both) of two things:

• A mismatch in authentication protocol or the server authentication is using an older protocol Apple has deprecated. e.g., if the connection is SMB, then NTLMv2 authentication should be the minimum/standard. If for some reason NTLMv1/LANMAN is being used, it won't work.
• Incompatible encryption or SMB versioning on the server. SMB 3 should be the standard, SMB 2 is a minimum and on it's way out and SMB 1 is long past being supported.

In any case, the issue is very likely on the server settings. What kind of server is it? Something like a QNAP or Synology SOHO NAS, or an actual Windows or Linux server? You mention your Mac and other Windows desktops, but not what the server is running...

QNAP still offers AFP, but in the relevant settings page it will tell you that AFP is deprecated and newer Macs use SMB. Honestly, unless there is some old computer that must use AFP, the admin for that device should disable it.

Apple almost completely gave up on its proprietary AFP Apple File Protocol decades ago, and adopted Microsoft Server SMB (Server Message Block) protocol. Apple has even made some improvement to the SMB Protocol. But even older versions of SMB should be well supported.

It is conceivable that if the connection type is so old that the encryption of the credentials is not secure, the Mac may refuse to make a connection. You should get a warning that this is not secure, and be allowed to proceed anyway. The long term solution would be to upgrade the Server to more modern protected login credentials.

When you attempt to view files on the Server, a dialog box asking for credentials appears on your Mac. Just to confuse you, the credentials required are the credentials required to log in and read files on the Server -- despite the dialog appearing on the screen of your Mac.

Grant Bennet-Alder wrote:

Apple almost completely gave up on its proprietary AFP Apple File Protocol decades ago, and adopted Microsoft Server SMB (Server Message Block) protocol.

Even so, the QNAP NAS on my office network offers up both SMP and AFP locations.

What address are you using to connect? On the Mac, it's normal to connect via samba, e.g. in Finder > Go menu > Connect to Server, the URL looks like smb:// followed by a numeric (IP) address or the server name such as SERVER.MYCOMPANY.LOCAL/SHARENAME.

the typical way to set this up is to connect the Sserver as just another device on the network, connected to your Router.

Then you connect your computer to the NETWORK, through your Router, using Wi-Fi or Ethernet as convenient for you. Data going locally uses only the network Switch portion of the Router -- it does not get sent onto the Internet.

There is no advantage whatsoever to trying to make a special connection to the Server using a separate Ethernet cable. if you have a spare Ethernet cable, connect it to your Router to speed up all your transfers, and make sure Ethernet is TOPMOST.

The settings in File sharing are used to make YOUR files (on your Mac) available to others. It is not applicable is this case.

Devices like your Server should just show up as an already-shared Network Drive, and invite you to log in, if possible.