A typical workflow is allowed to run for 1 minute (60 seconds). If the workflow is still running after this time, it will be interrupted and execution will end. This is considered a "workflow timeout".
Normally when a workflow times out, the workflow will produce an error log with the "error" key set to "workflow timed out". However, due to the nature of interruption, the workflow error reported may be different, so you can refer to the error log "deltaTime" (which is in milliseconds) to see if it has exceeded 60 seconds (60,000 milliseconds).
workflow timed out error log
different error log with deltaTime > 60000
If a workflow encounters more than 10 timeouts in an hour, or 20 timeouts in a day, the workflow will be deactivated and must be manually reactivated. This is to safeguard your resources from a misbehaving workflow, allowing your other workflows to continue processing.
For workflows that must run longer than 1 minute, you can enable slow-path execution (beta) which has a 20 minute (1200 seconds) workflow timeout. To do this, edit the Notes of the workflow (click the sticky-note icon in the top left-corner of the workflow canvas) and set the note content to match the following exactly:
Activate the new version of the workflow and it will execute in the slow-path. Note that your project has less slow-path execution resources than the normal fast-path. Overusing slow-path execution can lead to a backup in overall workflow processing.