Connecting a mailbox

To send campaign emails you connect a sending mailbox under Campaigns / email settings. You can connect Gmail or Microsoft/Outlook accounts. Each plan allows a certain number of mailboxes (Free 1, Scout 3, Hunter 10, Apex unlimited). Connecting more than one mailbox lets you spread sending volume and protect deliverability. On Scout and above, a newly connected mailbox can be put through a warmup period that ramps its daily limit up gradually to build sender reputation; warmup is not available on the Free plan, where each mailbox sends at its set daily limit from day one.