Came across this issue when trying to test a form with the HubSpot handler enabled.
Note: I have not "linked" the account yet, as I don't have HubSpot account login info. I have only filled in the HubSpot Portal ID, HubSpot Client ID, and HubSpot Client Secret.
Drupal\hubspot\Hubspot::submitHubspotForm(): Argument #1 ($form_guid) must be of type string, null given, called in /app/web/modules/contrib/hubspot/src/Plugin/WebformHandler/HubspotWebformHandler.php
Active
3.0
Code