Not getting mail

I'm not getting mail I am supposed to get.

Are any of your filters set to "Get rid of them (/dev/null)"?
This is the reason for 99.9% of the people who contact us about missing mail. They set a filter to delete the messages that match it and now the filter is matching against messages they did not think it would and deleting wanted mail. Two main filters that you should never have deleting: Banned vocabulary and Bayesian Filters. Banned vocabulary matches words or phrases against the entire mail: headers, encoded attachments, all. It often matches when you would not expect it to. Single words can randomly appear in encoded attachment text more often than you would expect. Bayesian filters are learning filters. You must actively manage them. Always! You cannot enable the bayesian filter, train it, then let it be forever. It keeps learning. If you set and forget it, it will somehow always manage to learn that every mail is spam.

Did any of your other filters catch the message?
Is it in your spam or bulk folder? Another folder?

Did the sender typo the address and write coste instead of cotse?
This is very common

Was it sent with a fake, antispammed, or typoed from address?
Most mail servers will refuse to deliver mail with a from address that cannot be verified via dns and because it is a fake return address the sender can't be notified of the failure

Did the sender get a reject message that explained why it could not be delivered and fail to read it?
In most cases (that aren't any of the above), the sender has received a notice of why the message could not be delivered...and did not read it or perhaps did not understand it (ex. our spam zombie milter).

If the sender did not receive a reject message the odds are very high that your e-mail filters deleted the message. This is because server failures will always result in a notice, while your mail filters will never provide a notice.

There are a vast number of reasons why mail may not make it's destination. We only included our end above, the senders server may not have even attempted delivery. We can only track what we receive. To track a received mail we need some key information:

We need the date and time it was sent.
We need the
to address.
We need the
from address.
It must be about a message sent
within the last five days or we will not have logs to trace back.

We must have all of this information. Without all of this information we cannot even look. Without all of this info we can only respond as follows:

"Given the information provided we are unable to determine what, if anything, happened."


Why this is:

Due to our unlimited aliases, multiple domains, free domain hosting, and mainly thanks to spammers, we process nearly five hundred e-mail connections a second. This creates an enormous volume of data. Given only the date and time we can cut down a ginormous volume of data into a humongous volume. This is due to clock discrepancies, time zone differences, and other things that render the date/time unreliable as an exact pinpoint, so we must have a slush on either side of that date/time. Lots of data still so we need to know who it was sent to as a further filter. We give unlimited aliases, we need the To address. Perhaps this will pinpoint it alone, but if that alias gets a bit of mail, we will need even more. We will also need the from address. All three guarantee that we can trace it if our gateway received it, well trace it up until it was handed off to your filters, anyway.