I can't see a NAS on my Network all of a sudden

This was working fine.  But I replaced my router today.  Everything seems to be working but now all of a sudden, I can't see a Windows 10 PC that I have set up as a NAS.  It was not working for a long time, but then all of a sudden it showed up on my old Router.  Now on this one I can't see it in Windows.  If I connect to my Router, I can see it.  I have put a box around the device that shows up when I connect to my router and you can see it in this screenshot I took:

When I open File Explorer, I can't see it on my network.  I tried connecting with Remote Desktop and that doesn't work either.

Can someone help please?

Thanks in advance

Jim S.