Since the release of Nextcloud 21.0.0, there have been increasing reports that cron and occ commands can no longer be executed. For once, these issues were not limited to Synology DiskStations or DSM. Since release 21.0.2, the error has disappeared for some users, but it persists for others. With 21.0.3 there were some changes that were actually intended for Nextcloud 22, but were quietly and secretly made for 21 as well.