Error when using google calendar API "Request had invalid authentication"

I'm using this API to get some events: https://www.googleapis.com/calendar/v3/calendars/primary/events?timeMin={time}&timeMax={time}Z&timeZone={zone}

And using a access token as a Bearer token. I used this request so many times and all worked.

Now I'm getting this error:

{ "error": { "code": 401, "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.", "errors": [ { "message": "Invalid Credentials", "domain": "global", "reason": "authError", "location": "Authorization", "locationType": "header" } ], "status": "UNAUTHENTICATED" } 

}