Hex RB750Gr3 issue

Hi.
I have an issue with hEX RB750Gr3. i can’t connect to hEX by MAC and by IP. hEX startup is ok , LED is ok, power is ok. RESET didnt help. i can reinstall software by NETINSTALL but after that i also can’t connect to hEX by MAC and by IP.
What else can i do ?
Thanks

Make sure you are connected to port 2-5.

yes, of course, but the same issue