I am having issues with the smart calendar app booking system, I followed the course and got stuck with the initialization portion of the API,…please help
Hello, @ijumucloud! Thanks for reaching out.
When you receive such an error, it informs you that on the API call initialization step there was some wrong/missing parameter.
For example, the error you have received tells you that you have not initialized the token.
For this, you have to preview your app page, login into the app under your Google account, and receive the “success” message:
Once your API is correctly set up as an OAuth provider, you can set up calls and use them in production.
Hope it helps! 
hello i followed your instructions and did just that, however i still get the same error and it doesnt initialize a call… not sure whats going on. help
As per my reply in Intercom:
Please make sure you have an existing event in the Google Calendar of the user you are login in.
Explanation: I am logging in as test@gmail.com email. Under my test@gmail.com Calendar I have an event on 10-07-2021. In the Free/Busy API Call I set the sart_datetime to 2021-07-01T10:45:15.378Z, end_datetile to 2021-07-31T10:45:15.378Z. Thus, I have an event in the date range indicated in the Free/Busy API Call - this will help to initialize the call successfully.
Please check and let me know.