ATV2 SMB trouble

I have two ATV2s, one in the living room, one in the bedroom. Both are hardwired to the router. Pc is running Win10, also hardwired to the router. Everything was working fine, until my provider upgraded my router. Took my old one and replaced it with a new dual band wireless router. This is the only change in my entire setup. Now, I can’t access my shared PC folders, and when I try to add new video sources I get Error 2 :share not available as soon as I select SMB from the protocol list. I’ve tried adding manually with both “1.2.3.4:445” and “\\1.2.3.4” formats with no success. I’m totally stumped. Any ideas out there? Thanks in advance!