How can I disable double opt-in confirmation? Watch video
To disable double opt-in, locate the field labeled Your current campaign in the upper right corner. Click the down arrow to select a campaign and click the gear icon to the right of the campaign name.
In the Permission tab, uncheck boxes under Enable confirmed opt-in section to disable double opt-in for email, web form and import subscriptions. If you leave the boxes checked the confirmation messages will be sent.