Why my mac can not access external traffic to other port except 80, 443, 22? I can access all website with standard port(80 and 443) example: domain.com, but why I cant access example.com:3030? I cant connect to MySQL and PostgreSQL, via direct host/port to external IP, but I can connect to MySQL from localhost.

I can connect to all external/public hostname/ip, if I try this command:

curl domain.com:6030


the result is 


  curl: (7) Failed to connect to domain.com port 6030: Operation timed
  out 


but I can connect to port 80,443 and 21.     I can open domain.com:6030 using another device, but why I can not using my mac?

How to fix that? I never turn on firewall.
Sorry all, the problem is caused by VPN application, after I turn off that I can access all port again. I didnt know if that running because that app not in the dock list, only in menu bar. 

Thank @jaume for giving me the clue about that app.