Error when sending and receiving text messages from two nodes

[ghost]

How do I go about fixing this error?

[gh0st42]

This indicates that no dtnd was started on the nodes, thus, the CLI tools get a connection refused when trying to communicate with the local dtnd instance.

As I have no idea what your prior steps were, I can only guess that you forget to start the dtnd or something went wrong while copying the binaries to the system. Instead of using cea as suggested in the guide, you can also just start dtnd interactively on each node by entering the commands (dtnd -n $(hostname) -e incoming -C mtcp -r epidemic) in one of coreemus terminal windows. If you followed the steps of the guide there should also be logs in each of the nodes for dtnd (nohup.dtnd.*.log).

For proper help you should also post instructions to exactly reproduce your issue and text is preferred over screeenshots. Also, we have a discussion board in the project where general help can be given. The issues are more for reporting bugs in the code itself, not user support :)