My scheduled documents are not run

All scheduling information is maintained by the Synk scheduler, which is a small independent program which always runs in the background. Scheduled runs cannot take place without the scheduler being present, nor can schedule information be saved.

To check whether the Synk scheduler is running:

Open Activity Monitor, at /Applications/Utilities/Activity Monitor.app
Enter "Synk" into the search box at the top of the window. The scheduler, if running, will appear as "Synk Scheduler."

If the scheduler is not running, follow the instructions at Why has my schedule gone blank? to reinstall the scheduler.

Other things to consider:

The scheduler will not run while Synk is open in order to avoid both Synk and the scheduler trying to use or run the same document at the same time. If Synk is open when the scheduled time arrives, the scheduler will try again each hour until Synk is not running anymore.
If you have moved the Synk application since you scheduled the document, you may need to save the document again using Synk in the new location. For security reasons, a scheduled document is always run by the copy of Synk which saved the schedule, so moving the application will break this link.