Do your incoming emails sometimes arrive late, delayed by minutes or even hours? I found it really annoying when it happened to me, especially when trying to sign up to websites that required a response to confirmation emails before letting me in. I’ve even travelled to a cancelled meeting because of email delays.
Here are the most common causes, and what to do about them.
If you retrieve your email the traditional way using the “POP” or “POP3” protocol, your mail program probably only checks for new messages every 30 minutes or so. This is called “polling” or “pull” email. It introduces a variable delay, often up to an hour.
How to tell if you’re affected: Check your mail program settings to see what protocol it’s using. Also, if clicking a “Send/Receive” or a “Refresh” button causes delayed messages to instantly appear, this is a likely cause.
What to do about it: Change to use the more modern “IMAP” protocol (or Microsoft Exchange) instead of “POP”, if possible. As well as effectively giving you instant “push” email delivery, this allows you to synchronise mail between different devices, organise messages into folders, train your spam filters and gives you a backup.
If your mail provider doesn’t offer IMAP, you may be able set up a simple forwarder to send all your incoming messages to a provider who does (e.g. a free Gmail account). It’s also possible to change your DNS settings (specifically your “MX” records) to reroute your mail without an extra forwarding step, but that usually requires a subscription to a service (for example, G Suite).
If that isn’t possible, try setting the delay to a shorter value in your mail program settings. Check with your mail host first though, because some will block you if you poll too frequently.
Greylisting is a simple and effective anti-spam technique that works by initially refusing incoming mail from unrecognised sources and waiting for a redelivery attempt. The problem is, it introduces unpredictable delays in the process, which can occasionally be severe (a day or more).
How to tell if you’re affected: Ask your email provider if they use greylisting. You can also examine timestamps in your email headers to deduce where delays are happening if you know how.
What to do about it: Ask your email provider to disable greylisting, or do it yourself if you have access to a hosting control panel. You will probably have to enable an alternative spam filter or forward your mail to a different account with a filter, otherwise you will be flooded with spam.
Incorrect DNS settings are a frequent cause of mail delays, in my experience. In particular, “MX” settings typically point to a different host or IP address than the “A”, “AAAA” or “CNAME” records for a domain, which is confusing. Even worse, once such a mistake is corrected, it can take many hours for the DNS changes to propagate and even longer for email senders to attempt redelivery, which means you may continue to see random delays for a couple of days.
It’s also really easy to misconfigure a mail server or client, resulting in a “forwarding loop”, “open relay” refused delivery or other problems that cause mail senders to blacklist you for a while. A simple change like setting an out-of-office notification can trigger a problem that may not be immediately apparent, and may take days to fully resolve once fixed.
How to tell if you’re affected: Send test messages to yourself from another mail account and check for bounce messages. If you don’t understand them, forward the bounce messages to someone knowledgeable using “forward as attachment”. You can also test your mail settings using MX Toolbox.
What to do about it: If you have recently changed your DNS or mail settings, get someone to check them. Otherwise, contact support at your mail hosting provider. Be patient once problems are corrected to allow fixes to take effect.