Open your Mautic settings sidebar and click on API credentials.
Create new oAuth2 credentials with the following values:
Name: As you like: E.g. Trello
Redirect URI: https://trello.aivie.ch
Click save and close
trello.aivie.ch adding to your CORS-Domains
If you have restricted your CORS domains (recommended), please add https://trello.aivie.ch to your “Valid Domains” in Mautic > settings > CORS settings.
If you enabled CORS just now, make sure your website and other external services can still connect to Mautic.