Connect the account
- Open Integrations → Marketing Automation.
- Find Mailchimp and choose Connect.
- Paste the API key from your Mailchimp Transactional account into API Key.
- Choose Connect and wait for the connection result.

Open Integrations and choose Connect on the Mailchimp card. External authorization is a separate step.

Paste a Mailchimp Transactional (Mandrill) API key in the connection form. This capture uses an empty field and does not connect an account.