Gateway does not register in Chirpstack 4.X installed on Vmware

Hello everyone. I ran it in Chirpstack 4.X vmware, on ubuntu server. I did the necessary port opening operations from my modem. (UDP 1700, TCP 8000, TCP 8080) I can reach the App Server. But 1700 won’t turn on. Dragino gateway does not register. What could be the problem? Is there a different port that I need to open from the modem or is there a different action I need to do to open LNS out? (LNS and gateway and nodes on the LAN are working normally.)

I don’t know what the issue is, but this guide might help you to debug the issue:

(you might want to look at the tcpdump commands to validate that UDP data is being received at the server side)