Please check that this widget Facebook Reviews has a connected Facebook.
Facebook API Error: {"error":{"message":"Error validating access token: The user has not authorized application 1501100486852897.","type":"OAuthException","code":190,"error_subcode":458,"fbtrace_id":"AO9HVBB2dIxjh7l1iL8PkN4"}} Reconnecting to Facebook may fix the issue.