Email Stopped Working After a Nameserver or DNS Change Print

The symptom

Your domain's nameservers were changed, or the domain was transferred, or your website moved to a new server, and now email is misbehaving. The usual signs:

• Some mail arrives and some doesn't, with no obvious pattern.
• Mail works for some people but not others, or works on your phone but not your desktop.
• Senders report delays or bounces, but only for a day or two.
• Old messages seem to have vanished, or new mail is arriving somewhere you can't see.

This mixed, inconsistent behaviour is the signature of DNS propagation: the period after a DNS change during which different networks around the world still have the old information cached and are acting on it.

Why it happens

When your domain's DNS changes, the rest of the internet does not find out instantly. Every network keeps a cached copy of your domain's records and only refreshes it when the cache expires, which can take anywhere from minutes to 48 hours depending on the network. During that window, some mail servers are delivering to your new mail server and others are still delivering to the old one.

This is why the symptoms look random. Whether a particular email reaches you depends on which cached copy the sender's mail server happens to be holding at that moment.

The good news is that email is built to survive this. Mail servers that can't deliver immediately queue the message and retry for several days, so mail sent during the transition is very rarely lost outright, it is either delayed, or delivered to the old server.

What to do

1. First: wait, deliberately. If the change happened within the last 48 hours, inconsistent email is expected and usually needs no fixing. Resist the urge to make further DNS changes during this window, each change restarts the clock and makes the situation harder to diagnose.
2. Check the old server's mailboxes. If your old hosting is still active, log in to its webmail. Mail delivered there during propagation is sitting in those mailboxes and can be forwarded on or collected before the old service is cancelled.
3. Do not cancel the old hosting until propagation is fully complete and you have retrieved anything that landed there. Cancelling early turns "mail delivered to the wrong place" into "mail bounced."
4. After 48 hours, if problems persist, it is no longer propagation. At that point the likely causes are incorrect MX records at the new DNS host, a missing mailbox on the new server, or the Email Routing issue covered in our article on mail going to the wrong place after moving providers. Open a support ticket, tell us what changed and when, and include a bounce message if you have one, and we will check the records directly.

Planning a change? Do it the smooth way

• Lower the TTL in advance. If you know a DNS change is coming, we can reduce the cache lifetime on your records a day or two beforehand, which shrinks the propagation window from up to 48 hours to minutes for most networks. This only helps if it is done before the change, ask us when planning, not after.
• Create the mailboxes on the new server before switching, so that mail arriving early has somewhere to land.
• Schedule changes for your quietest period, typically a Friday afternoon or weekend for most businesses, so the transition window overlaps with the least important mail.
• Tell us it involves email. A website move and an email move are separate decisions. If your email should stay where it is while the website moves, say so, and we will make sure the MX records carry over unchanged.

Good to know

You can watch propagation happen using a free tool such as dnschecker.org, enter your domain, select MX, and it shows which DNS servers around the world are seeing the new records versus the old ones. When the results show the new values everywhere, propagation is done, and any remaining email problem has a different cause.