FRITZ!DECT 210 Service - Knowledge Base

FRITZ!DECT 210 Service

FRITZ!Box reports "Internal system error (17) occurred" when adding a Google calendar

When setting up automatic switching for FRITZ!DECT, you cannot add a Google calendar. During the authentication process, the error message "The authentication process for the Google Calendar on the FRITZ!Box could not complete the procedure successfully. Internal system error (17) occurred" is displayed.


  • The calendar was not set up on Google yet or was not set up correctly, or the name of the calendar contains illegal characters, or it is misspelled.

1 Correcting the name of calendar

  1. Sign in to your Google account.
  2. Rename the calendar you want to use for the smart home device: Remove all special characters, spaces, letters with umlauts, or accented letters from the calendar's name. The name may only contain standard letters and numbers.

2 Adding a calendar

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