Access to Home Assistant in LAN with PLC device

I am using Netgear PLC devices to extend my LAN using my inhouse power line.

One of them is connected to my home gateway and the other one to switch. This switch is connected to Raspberry Pi with Home Assistant. Netgear devices are rather transparent when it comes to IP accessibility. IP address is given by my gateway to devices connected to it directly as well as through Netgear.
When my phone is connected to Netgear wifi I can access Home Assistant. However, when I am connected to wifi from gateway I cannot connect through browser using homeassistant.local, IP address, cannot ping or ssh. This Netgear with wifi is connected with Ethernet cable to my gateway. So in both cases communication goes through power line.
I have never had such problems with other devices. They were always visible in one LAN as they have IP addresses from the same network. This is very strange. I observe such behaviour first time. I have never had such connectivity problems.