patch
https://app.mailivery.io/api/v1/campaigns//start-warmup
Begin warm-up sending for a connected mailbox (campaign). Before sending starts, Mailivery verifies both SMTP and IMAP connectivity — if either check fails, warm-up will not start and you'll need to update the mailbox credentials and retry. Use this endpoint for a brand-new campaign, or after a pending Microsoft mailbox has finished OAuth consent.