Some computers (various macOS and iOS versions, for instance) or network routers (with some firewall options enabled) won't forward UDP broadcasts, which typical OpenHPSDR METIS Protocol 1 negotiation to find an HL2 seems to require.
If you know the DHCP IP range that your router provides to its local subnet, you can do a very manual discovery search for the HL2's IP address. Unplug the HL2 then ping every address in the IP range, plug the HL2 back in, wait for the LEDs to indicate it's network is up, then ping for any newly appearing IP address, which is likely the IP address of the HL2 just turned on.
If you can compile and run hl2_tcp (on GitHub), then you can also send directed (not broadcast) UDP discovery packets to an HL2 using the -d option.
> hl2_tcp -d 192.168.10.4
or use your suspected IP address. The HL2 will respond to any UDP discovery message, broadcast or directed.
73, Ron, N6YWU