This page will help you troubleshoot issues with receiving mail from a specific person.
Good email being blocked is unacceptable to us. We follow a zero false positive goal with our spam filtering. We'd rather let another piece of spam through than block a good message. Great care is taken to ensure this goal is met.
Our mail server's spam filters have been built in-house and we don't block or allow any specific senders. Instead, our spam filters adjust automatically based on sending patterns and use public reputation data on sending mail servers and domains. It's one of the best in the industry and we work hard to keep it that way.
Why is it Being Blocked?
If a blocked good message does occur, it's almost always due to one of the following reasons:
- The sending mail server's ip is blacklisted as spam source on a widely used public list
- The content of the message contained a domain that is blacklisted as a spam source
- The message hit another one of our other spam filters
- The sending mail server is misconfigured
Our filtering is done in-line, which means messages never "disappear". Because of this, if we reject a message for any reason, the sender will always receive a bounced message. This bounced message will include the reason why the message was rejected and how the sender can fix it.
We use a combination of blacklists to check for and reject spamming emails; Spamhaus and SURBL are two examples. These lists are used by many other mail servers and we've found them to be very accurate. The only time people have any issues with them is either due to a real spamming URL/IP or a URL/IP that the sender needs to get delisted.
Sending Mail Server Misconfigured
One issue with the sending mail server could be a lack of Reverse DNS. Most mail servers (including ours) require Reverse DNS to be setup on the sending mail server in order for mail to be accepted from them. If it isn't, then it will be rejected. The sending mail server could have also had an issue on their end resulting in the message not being sent at all.
External Spam/Virus filter
An external spam/virus filter such as McAfee and AVG can interfere with received mail. This could occur if you use an email client (ie. Outlook) to check mail as the messages will be first filtered through the external spam/virus filter.
Our mail server is designed to not need whitelists. If an email is being flagged by one of the public blacklists we use, the sender needs to get their name delisted. Chances are very high they're having problems with other mail servers as well. Whitelisting them on our end would risk having ourselves blacklisted by other mail servers, which would affect deliverability for all our customers. The bounced message includes the reason the message is being rejected.