Campaigns in the app started failing because some datasets could not be accessed.
Datasets were showing the message "This Dataset has not been accessed in a while…"
While clicking the Start button resolved the issue, I would ask that the Campaign App be updated so that it flags the dataset as accessed.
Sometimes the only purpose of a dataset is a campaign, and currently the dataset will show as unused. Therefore I would also request that the Campaign App show up under the Impact section when deleting a dataset, or perhaps under the Linage section of a dataset to show that it is being used.
