Configured with Service account but instance runs with "app@SharePoint". Works fine when manually triggered but errors out when scheduled.
Hi what kind of action are you performed ?
The app@SharePoint are the identity of the "Workflow App". So may be the workfow app have'nt the right to perform some of your workflow actions.
Have you try to enable the Feature : "Workflow can use app permissions" ? (this feature is required to scheduled workflow in O365)
We have used Query List and other basic actions in our workflow. Tried re-activating the feature but still the workflow gives 'Cannot complete this action' when run on scheduled time.