Cannot connect Raspberry Pi with iC880a to V3


I have a problem connecting my gateway consisting of:
Raspberry-Pi2B and LoRaWAN concentrator iC880a (SPI)
to TTN V3 servers.

I was using this gateway for more than a year before May 2021 and it was working fine. I want to continue with my work but after I followed the steps for adding GW to V3 console but my GW status is still Disconnected.

For configuration I followed the steps here:

It should be updated for the V3.
Only change from V2 in the script seems to be gateway server.

I tried all the basic troubleshoting like reseting, restarting, registering again, checking connection(I can ping

I didnt found the solution on the forum. (Sorry if I overlooked something).

If somebody could navigate me what should I do or send me a link with solution that would be great.

Thank you in advance

Here you can find a tutorial for a RasperryPI + IC880A-SPI gateway setup.