Mac mini m4 sequoia 15.3.2 simple smb share doesn't work

Hi,

New Mac mini M4 base with 1gbe. I am trying and failing to set up a simple SMB share. The share is on a Samsung 990 Pro 4TB, inside and OWC 1m2 enclosure, plugged into the far left back (looking from the front) thunderbolt port of the Mac mini M4. This works perfectly as is, no issues at all.

I need to set up an SMB share for some of the folders on the drive and be able to access them from my MacBook Pro M3 Pro. Both machines are running Sequoia 15.3.2.

I enabled file sharing on the Mini, set up a folder, which was two directories in from root. Made sure the user had permissions to read and write and that full disk access was not selected . I enabled SMB. Initially left the windows section unchecked. Rebooted the Mac mini.

From my MacBook, in finder, I did ctrl k and added the Mac mini's ip, but also tried with local host name, and if I try macminisIPaddress/folder/sharedfoldername, I get an error saying 'There was a problem connecting to the server "192.168.*.*" The Share does not exist on the server. Please check the share name and then try again.'

If I then do the same but without the folder/shared folder name, it brings up a little menu of folders to log into, most of which should not be shared, apart from the shared one. There are Macintosh HD, Adminname account, 990Pro4TB. Oddly, despite not checking full disk access, I can log onto Macintosh HD with full disk access, which is kind of worrying. and When I try to log into the shared folder, it says no such directory, even though it gave me the correct folder as a choice.

Another odd thing that I keep seeing, is the admin account name for the mini, which is listed in the file sharing section for windows machines, is listed twice or 3 times. It isn't listed anywhere else more than once, just there.

I have tried to make a new user with admin permissions, and removed all the others from file sharing, but the same thing keeps happening. Tried with firewall off on and on both machines, same behaviour.

I have been at this for days, with my limited knowledge and skillset and I am struggling. I have been through every video, every website that I can find, and nothing has helped.

Mini is connected via ethernet direct to the router. MacBook is connected via 6ghz wifi.

I don't suppose that anyone here may know what the problem is? Any help would be very much appreciated, thank you.