Reasons Why Valid Emails Are Hard Bouncing
Hard Bounces are emails which have permanently failed to deliver to a recipient. Either the email address does not exist, the domain no longer exists, or your recipient's email server has rejected your email. There are several reasons why an email address, which you know to be valid, is hard bouncing when you're sending campaigns to the email address via Campus.
Blocked by Security Software or Spam Filters
It's possible that your campaign has been blocked by the recipients' spam filter. A spam filter might have blocked your email for a number of reasons; from the wording in your email, the colour(s) used in your email background, to strict firewall rules which block any unknown IP addresses. Have a look at our article How to Beat a School's Spam Filter to see if there's anything in your campaign content which you think you could change.
Is Campus blocked?
You might find that a one-to-one email which you have sent to a recipient via Campus or your own external email client gets through (confirming that you know the email address is valid), but that the same recipient is unable to receive a marketing email. This is because their server knows if the email is a one-to-one email or a mass marketing email, and they might interpret the latter as spam.
The best way to avoid this, (although not always possible) is to ask the recipient to ensure the following IPs are whitelisted at their end to ensure deliverability in the future;
IP Addresses
- 185.254.91.208
- 185.254.91.68
- 185.254.91.101
- 185.254.91.209
- 185.254.91.221
- 185.254.91.207
- 185.254.91.91
- 217.10.154.38
- 185.254.91.89
- 217.10.154.40
- 185.254.91.88
- 217.10.154.42
- 185.254.91.87
- 217.10.154.44
Internet-based Mail Service Providers
Some internet-based mail service providers, such as Gmail or Hotmail, will implement a number of controls that protect their users from receiving unsolicited emails. The logic that they employ to protect their users can sometimes catch emails from Campus. These are often based on the same reasons talked about earlier in this article but they do not actively publicise what they block as this would give real spammers information on how to bypass these protections. This is an issue that affects all marketing platforms, not just Campus. Minimise the chance of getting caught out by these spam filters by following best practices.