Topics not visible on two machines

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I am running ROS master on my PC and robot on embedded machine that connects to it. Recently, I have changed the embedded machine (before that, everything worked) and suddenly I cannot see remote topics on both machines (only local). My host PC runs Melodic and Embedded runs Kinetic but it should not matter as messages are the same.

From my host PC, I was able to SSH into my embedded machine and ping data. Also, I have added both machines in /etc/hosts, I have set the ROS_IP on both machines and I set the ROS_MASTER_URI on both machines with the host PC IP Address.

What could be wrong?

EDIT:

I also checked the netcat from this page: http://wiki.ros.org/ROS/NetworkSetup

I can confirm two machines can communicate