We had two established and working dataflows that all failed during their scheduled refresh last night/ this morning citing:
Error: Data source credentials are missing or invalid. Please update the credentials for Cds in dataflows settings page and try again.
Both of these were refreshing from a Microsoft datasource (Dataverse for one, Sharepoint List for the other). Opening the dataflow and re-signing in seems to have resolved the issue, but I'm unsure how the dataflow lost it's credentials. One of the dataflows' signed on user had their password updated yesterday, but I don't remember previous password changes causing this kind of failure.
