Sometimes your email delivery can be affected by "blacklists," which are lists of IP addresses of known spammers or servers that could be a potential spam threat. If an IP address is on the list, the email may have difficulty being delivered to your recipients.
First, if an IP address is on a blacklist, the turn-around time for getting it de-listed from any major blacklist, like Spamhaus or Spamcop, is usually one business day.
One of the unique features of the SCBL (Spamcop Blacklist List) is that listing expires automatically when no spam is reported for that source for 24 hours.
Our delivery team works hard to maintain a high sending reputation to avoid situations like this which is why it's important that you are are utilizing the best sending practices that you can.
To learn more about how to avoid being marked as spam, feel free to check our our How to Avoid the Spam Folder webinar: