Netcat connection not working both ways (Mac-Kali), connection refused

Question

I was following this website in order to establish a netcat connection. I have a mac and a kali virtual machine. If from my mac I type nc -lv 1234 and from kali I type nc ip.of.my.mac 1234 then the netcat connection is established. However, if I do the reverse, i.e. on my kali I type nc -lv 1234 and on my mac I type ip.of.my.kali 1234 then I get nc: connectx to ip.of.my.kali port 1234 (tcp) failed: Connection refused. Could you help me to debug the issue?