OMV on Raspberry Pi Media Server - Windows 11 Error (0x80070035)

I've just built a new PC and installed Windows 11 on it.

I have a home media server which I built using a Raspberry Pi 4 and the openmediavault package.

My previous PC (running Windows 10) could connect to my media server no problem - it's only 2 or 3 days since I was doing this, and it worked fine. I had shared folders on the server mapped to drive letters in Windows File Explorer - the usual kind of thing.

The server itself seems to be behaving completely normally - I can access it from my other devices (iPad, Apple TV, etc.) with no problems, and on my new PC I can see the OMV dashboard on my web browser - all working fine.

Pinging the server from my new PC works fine, so the connection between the two is intact. I can SSH into the server using Powershell on my new PC, and that's fine too.

But in Windows File Explorer I can't access the server. It shows up as an item under the "Network" tab, but when I click on it I see: "Windows cannot access \\<server name> - check the spelling of the name. Otherwise, there might be a problem with your network. To try to identify and resolve network problems, click Diagnose"...and at the bottom "Error code: 0x80070035 - the network path was not found".

Clicking the "diagnose" button doesn't help - the Windows thingy doesn't find any problems.

Does anyone know how I can fix this please? I tried to follow some guidance from ChatGPT but it just went round and round in circles and was unsuccessful.

Thank you.