Get stuck in wait_heartbeat() in Pymavlink HereLink

Question

I am quite new to HereLink and Pymavlink.

I have a HereLink RC controller connected connected to a Linux machine. RC is paired with Airunit:

Air-unit ← - - - - - - → RC ↔ Linux machine (with pymavlink running)

Inside the Linux machine, I have a very simple Python script:

master = mavutil.mavlink_connection('udp:192.168.144.133:14550', baud=57600)

master.wait_heartbeat()

while True:
    try:
        print(master.recv_match().to_dict())
    except:
        pass
    time.sleep(0.1)

My code gets stuck at wait_heartbeat() function. If I open QGC app on my Linux machine, this wait_heartbeat() function starts working and then I start receiving messages. Looks like QGC is doing a magic behind the scene that I am not aware of.

I would highly appreciate if anyone can help to spot the reason and logic behind this :)