A follow-up message is sent in case a user does NOT reply to your initial outreach message. You can setup follow-up messages to go out between 1-7 days after your outreach message.
The goal of this message is simply to bring your DM back to the top of the users requests inbox.
The follow-up message counts towards the limit of 50 DMs a day. Some users will not allow you to message them again without accepting your request. In those cases, we skip the message and move on to another user.