Windows 10 Lenovo laptop "destination host unreachable" when pinging from desktop on home network

[vannac]

I recently bought a used Lenovo T460s laptop (fully reimaged). I wanted to use it to RDP to my desktop computer (custom build, see specs here: https://pcpartpicker.com/user/vannac/saved/8zTNpg) while I am at home, but RDP wasn't working. Both systems are running Windows 10. My router is an Asus GT-AC2900. When I try to ping either the laptop or the PC, I get "destination host unreachable". But this is the weird part...both my desktop and the Lenovo laptop are able to ping/RDP to a third host that I have on the same network/subnet! To me, this rules out a lot of host side configuration issues, because if it was a firewall or network config problem, then I shouldn't be able to communicate with a third unrelated host on the network. I'm really left scratching my head on this one and I'm hoping the forum might have some creative ideas to try...

 

Things I have tried so far:

- Confirmed that I can see both desktop and laptop in the Network map on the router admin page. Both have IPs that have been assigned via DHCP.

- Confirmed both desktop and laptop are on the same network/subnet/gateway

- Confirmed both desktop and laptop are set on a "Private" network in Windows (should allow network communication between hosts)

- Confirmed ICMP/Echo is allowed in the Firewall rules for BOTH hosts

- Tried completely disabling Windows firewall on both the laptop and the desktop, no change to the network connectivity

- Removed any proprietary Lenovo software on the laptop in case it was enforcing strange security rules (still should not apply to a single host on the network). I'm not running any special Antivirus on either machine.

- Ran "arp -a" and confirmed that neither the desktop nor the laptop are listed the table shown after issuing this command. According to Google, this indicates a problem with a missing route, but there is nothing out of the ordinary in the router settings and the IPs have been assigned automatically with DHCP. 

- Tried connecting the laptop via ethernet cable to the router to rule out wifi, no change in behavior

 

In summary: what would prevent a specific Windows 10 host from communicating with another specific Windows 10 host on a 192.168 network? These are the only two systems with any communication issues as far as I can tell. Again, both systems are able to ping/connect to other hosts on the network.

 

Thanks in advance!