Don't be worry about the NOOB thing. 
We all start somewhere... When it comes to the issue, whatever it is, we don't know what we don't know. It's a matter of trying to work through it.
the issue/problem is probably so simple that I am overlooking it.. I cannot explain why it does not work.... sorry for being such a NOOB.....
My concern here is that the original problem seems to have migrated. Originally, your client could "see" OMV, but it couldn't connect. That would, most likely, be a permissions issue. That seems to have changed in that now, the OMV server is no longer visible. That's another issue altogether which would, most likely, be network related.
If you can't "see" OMV, under networks, that may mean SMB port(s) are being restricted. This is what makes me think that a firewall or some other Windows network restriction may be involved. Port 445 (TCP) is the port used for SMB 2.0 and up. (The older legacy ports, for SMB1, are TCP/UDP 137 to 139.)
If you're connecting to the console of OMV (you are) that means network connections to port 80 are allowed. Outgoing to Port 80 is allowed, by default, by nearly any firewall to allow web browsing. Outside of that, with freaking Windows involved, OEM window installations try to "help us" by locking down our PC's. The problem becomes, "how they do it". Add-on's like Norton (anything) can add additional complications as they try also to protect us from ourselves.
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- On the Windows Client, Go to the Start Button.
- In the "Search" line, type powershell and hit enter.
- Copy paste in the following line into powershell substituting your server's IP address.
Test-NetConnection 192.168.0.55 -Port 80
#The above is a test that should show "true".
#Do the same again, using 445 as the port.
Test-NetConnection 192.168.0.55 -Port 445
Following is my result from a Win10 client. The Win11 laptop is the same.
(I threw a failed result in there just as a reference.)
Finally see of your client is "listening" to SMB ports by copying and pasting in the following:
Get-NetTCPConnection -LocalPort 139,445 -ea 0 | select Local*, Remote*, State, @{n="ProcessName";e={(Get-Process -Id $_.OwningProcess).ProcessName}} | ft -Auto
