FRITZ!Box 7330 Service - Knowledge Base

FRITZ!Box 7330 Service

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

In the profile of FRITZ!DECT, for example FRITZ!DECT 200, 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.

Note:The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

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. Click the button (Switch Automatically) next to the respective device or any smart home device that belongs to the group.
  4. Click the link "Remove connections from Google calendar".
  5. Click the button "Reset Google Calendar".
  6. 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.