What it is
The Confirmation request is an automated email sent to recipients that have been imported and/or have subscribed through subscription forms so that they can confirm their intent to subscribe to the list.
Why use "double opt-in"
Sending prospective new subscribers to your list a request to confirm their intent to subscribe is an email marketing best practice. It's called double opt-in or confirmed opt-in. It's the only positive way to prevent invalid email addresses and "spamtraps" from being added to your recipients' database as subscribers since only humans actually interested in receiving messages from you will click on the confirmation link.
Please note that MailUp considers the subscribers' consent collection a fundamental requirement.
If according to your evaluations, you may require to collect subscribers' consent. In this case, you can import again your contacts using the confirmed opt-in procedure. But, be aware that only a low percentage of your database will confirm their subscription.
How it works
In the Request confirmation section, accessible through Settings > List settings > Notification messages > Confirmation requestthrough Database building > Subscriptions > Confirmation request email, you can find all the eligible messages to be used as confirmation request message and/or the active message, if any.
To enable a message, from the Actions menu on the right, select "Enable notification".