You see a failed tracking request with this error message when you use specific tracking parameters as part of the HTTP tracking API without authenticating the request correctly. Some parameters that require authentication are for example cip (forcing a specific IP address), or cdt (overrides the datetime of the request).

When such an error occurred, you need to make sure to set a token_auth of a user with at least write permission. If you have set a token, check the set token to make sure it is still the same and no copy/paste error has happened.