Selected input unavailable

A node reads a data source or scenario that is no longer available to it: it was deleted, or the selection names something outside this project. Before a run this stops the workflow from starting. If the input was deleted after the run was queued, the run fails before it reads anything.

What to do

Open the node the message names and select an available data source or scenario, or upload the file again, then run the workflow.

Where it comes from

Checked before every run, for any node. It is one of the messages checks before a run.