Reply is connected to your email account by IMAP (receiving emails) and SMTP (sending emails) settings.
Email account specified in IMAP section is the one we check people's replies in. The system is checking for replies each hour, but if there was any connectivity error, the detection can take more time (up to 3 hours maximum).
Please note, that all replies should stay in the main folder for at least 3 hours in order for our system to have time to detect them.
Also, don't move the emails anywhere to another folder, otherwise Reply won't be able to detect them and mark people as Replied. This will lead to the follow-up emails being sent to those who already replied.
Reply only detects responses received from the same email address as it's in Reply campaign and sent email to. If a prospect is replying from another email address, it won't be detected.
Reply don't detect forwarded emails.
If you are a Outlook desktop email client user, please make sure your emails are not auto-deleted from the server. After Outlook downloads your email, all the email messages on the server are deleted from the Inbox and Reply isn't able to detect the replies.