If you run avahi-browse --all on the Linux box (assuming avahi is installed, it probably is) it will show all the mDNS services that are being advertised on the subnet. Is the LE box visible there? .. e.g.
Code
ROCK5B:~ # avahi-browse --all | grep RPi5
+ eth0 IPv4 RPi5 _ssh._tcp local
+ eth0 IPv4 RPi5 _sftp-ssh._tcp local
+ eth0 IPv4 root@RPi5 _pulse-server._tcp local
+ eth0 IPv4 root@RPi5: Null Output _pulse-sink._tcp local
+ eth0 IPv4 RPi5 eventserver _xbmc-events._udp local
+ eth0 IPv4 RPi5 jsonrpc-tcp _xbmc-jsonrpc._tcp local
+ eth0 IPv4 B827EBB5E9A2@RPi5 _raop._tcp local
+ eth0 IPv4 Librespot@RPi5 _spotify-connect._tcp local