ROS2 nodes works on single machine but not across different machines

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Hello! So I'm just starting to learn ROS2 and I've created two ROS2 nodes which send a video stream from the webcam of one node to another that receives and displays it. This works when I open the two nodes on a single machine. However when I try the same thing on a network through two machines I get this error:

terminate called after throwing an instance of 'rclcpp::exceptions::RCLError' what(): failed to publish message: cannot publish data, at /tmp/binarydeb/ros-dashing-rmw-fastrtps-shared-cpp-0.7.4/src/rmw_publish.cpp:52, at /tmp/binarydeb/ros-dashing-rcl-0.7.5/src/rcl/publisher.c:257

I know that the two machines do see each other and can communicate as there are a few instances where the window to view the video stream will pop up. However 90% of the time I get hit with that error.