Mixpanel has introduced a new authentication method by the use of a “Service Account” as they are moving away from the usage of “Project Secret”. A service account will generate a username and a secret which will need to be added in the authentication flow in Funnel.
The new method is introducing more security for the user as they are able to better control which permissions are given as well as making it easier to revoke access completely. The service account is created by the user in the Mixpanel UI, more information can be found in the article How to connect Mixpanel.
This means that new Mixpanel data sources will need to be authenticated using a Service Account, this also applies to reconnects.