Are you finding that your poller configuration is set up properly for the necessary fields on your given connector 's endpoint, but your poller still returns no events? 

First confirm that your updatedDate and createdDate fields are correct. If they are, verify that the createdDateTimezone and updatedDateTimezone are correct for your tested account.

For this example, I will refer to the Pardot connector , but similar steps can be used for other connectors including Freshdesk and Jira.

1. Log in to your Pardot account and review the Default Time Zone setup for your user.
2. Make a GET call to the endpoint that you are polling, and retrieve a record that you have updated recently.
3. Review the response body and confirm that the updated date field reflects the same time zone that your account is configured for.
4. Include this timezone in your polling configuration. For example edit your connector instance, enable polling events, choose your object to poll on, and then click  on the right side to edit the configuration.
5. Review your setup and configure the time zones to appropriately reflect your account setup.

{
  "contacts": {
    "url": "/hubs/marketing/contact?where=updated_after='${dateTimeZone:MST:yyyy-MM-dd'T'HH:mm:ss}'",
    "idField": "id",
    "datesConfiguration": {
      "updatedDateField": "updated_at",
      "updatedDateFormat": "yyyy-MM-dd HH:mm:ss",
      "createdDateField": "created_at",
      "createdDateFormat": "yyyy-MM-dd HH:mm:ss",
      "createdDateTimezone": "MST",
      "updatedDateTimezone": "MST",
      "createdCheckTolerance": 0
    }
  }
}

For additional reference, see the developer docs on Polling.