If you just started working in IPA, some of the documentation is not straight forward and can often even be confusing at times.
The “No Incoming Connection” error is a simple fix for most nodes that do a query or write/read on a file.
Example of a No Incoming Connection error:
To resolve, select the connect tool and connect the Starting node with the end node to resolve the issue.
Done! These types of nodes should already come connected and if the developer needs to change them up that would be up to them. Good luck with the rest of the little quirks of IPA!