FRITZ!DECT 210 Service - Knowledge Base

FRITZ!DECT 210 Service

FRITZ!Box reports "Authentication error occurred" when using Google calendar

In the profile of FRITZ!DECT in the FRITZ!Box user interface, the error message "Authentication error occurred." is displayed for the Google calendar on the tab "Switch Automatically".


  • The FRITZ!Box's access rights to the calendar were revoked in the Google account.

1 Deleting a calendar

In order to request access rights for the calendar again, you must first delete all of the Google calendars in the FRITZ!Box:

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Smart Home" in the "Home Network" menu.
  3. If available, select the option "All smart home devices" in the drop-down list "viewing" if you assigned the Google calendar to one single device; select "All groups" if you added the Google calendar to a group.
  4. If you want to delete the Google calendar that you assigned to an individual device, click the button (Edit) for the respective device or the button (Switch Automatically).
  5. If you want to delete the Google calendar that you assigned to a group, click the button (Edit) for the group or the button (Switch Automatically) for any smart home device that belongs to the group.
  6. If available, click on the "Switch automatically" tab.
  7. Click the link "Remove connections from Google calendar".
  8. Click the button "Reset Google Calendar".
  9. Confirm the question about whether you would like to delete all Google calendars from the FRITZ!Box with "OK".

Now all Google calendars are deleted and all smart home devices that use a Google calendar are set to manual switching.

2 Adding a calendar

  1. Add the Google calendar for the smart home device.