Ethernet connection troubles

Hi all,

I read and tried to follow several posts here and on YT to connect a companion PC (Raspbery Pi 4) to a Herelink 1.1 Air Unit via its Ethernet port.

My setup is as follows :

PC (via Ethernet : ↔ Herelink Air ( ↔ Herelink Ground (

I cannot detect the Herelink Air Unit on the companion PC, the RJ45 LEDs turn on intermittently.

Does anyone of you know what I am doing wrong ?

Thanks for reading me.