Two collaborating cannot talk to each other

Hello, all

I am having 2 azure VM need to talk with each other.

Machine A, public ip 191.238.163.110 and private ip 100.75.252.154

Machine B, public ip 191.238.241.169 and private ip 100.75.142.101

In machine A, I am having bats-server listening on port 4222, and machine B want to access 4222 on machine A.

I had add the endpoint 4222, but on machine B it shows it cannot connect to machine A.

tcp        0      1 B:41353   A:4222  SYN_SENT   

tcp        0      1 B:41345   A:4222  SYN_SENT   

tcp        0      1 B:41348   A:4222  SYN_SENT   

tcp        0      1 B:41349   A:4222  SYN_SENT 

It's always SYN_SENT status.

I tried both the public/private ip, but they didn't work.

Also I cannot telnet to A using telnet A 4222

Is there anything wrong here?  Thanks for feedback in advance.