A task or list is missing
Check the selected list, search text, and tag filter. Choose Reset filter and check All for open tasks. Load completed tasks or open Completed if the task may already be finished. Expand a parent’s hidden subtasks. Smart Collections can be hidden in Tasks settings even when the underlying tasks still exist.
Event-only calendars are not task lists. An event shown in Calendar is not automatically a task. If you expect a task stored in a mixed calendar, check that same list in Tasks and confirm it was saved as a task rather than an event. Look in the Tasks trash bin if the task or its whole calendar was deleted.
Changes are not synchronizing
Keep the page open if Tasks reports a save error. Check your connection, then refresh after saving has finished. In an external app, confirm you selected the correct LightDrive task list and enabled its synchronization. A task stored only on the device will not appear in the Vault.
For connection checks, see 6.9 Troubleshooting Calendar Sync and 13.7 My Calendar Is Not Synchronizing.
An external app shows events but no tasks
Confirm that the app supports CalDAV tasks/VTODO and has a task list selected. Not every calendar app supports tasks. A public read-only calendar subscription contains events only. Follow 16.8 Synchronizing Tasks with Other Apps for the authenticated connection.
A reminder did not appear
Check the task’s saved reminder, start or due date, and time zone. A due date by itself is not a reminder. Check the Vault notification bell; do not assume an email or device pop-up will be sent. Completed, canceled, or deleted tasks no longer receive pending LightDrive reminders, and reminders missed more than 24 hours ago are not replayed. After a recurring task advances, check its next reminder.
If an external app handles local alerts, also check its synchronization, notification permissions, and battery restrictions. Those alerts are separate from the Vault bell. For a continuing problem, contact Support with the approximate reminder time and time zone; do not send your password or an unredacted task export.
A task appears twice
Check whether the app is showing both a local copy and the LightDrive copy, whether you imported an export, or whether two connections synchronize the same list. Compare the copies before deleting anything: deleting a synchronized task can remove it on your other devices too.
A password is rejected or a certificate warning appears
Use your full LightDrive email address and a credential accepted for CalDAV. A LightDrive client password must include Calendars; Email-only or Contacts-only access is not enough. See 13.2 My Password Does Not Work in an App.
Do not bypass a certificate warning or disable verification. Follow 13.9 I Received a Certificate Warning.