How to Fix Email Not Receiving on Custom Domain

Few things are more frustrating than discovering that your custom domain email isn't receiving messages. Clients are emailing you, but nothing arrives. Forms on your website seem broken. Important messages are disappearing into the void. Don't panic — most email receiving issues have straightforward causes and fixes. This troubleshooting guide walks you through the most common problems and their solutions.

Quick Diagnostic Checklist

Before diving deep into troubleshooting, run through this quick checklist to identify the most common culprits:

1. Is the problem with all incoming email, or just from specific senders?
2. When did the problem start? Did you recently change DNS records, switch providers, or modify settings?
3. Can you send email from the account? (Sending works but receiving doesn't points to MX record issues)
4. Are messages going to spam instead of the inbox?
5. Is your mailbox full?

Problem 1: Incorrect or Missing MX Records

This is the number one cause of email receiving failures on custom domains. MX (Mail Exchange) records tell the internet where to deliver email for your domain. If they're wrong, missing, or pointing to the wrong server, no email will arrive.

How to Check

Use MXToolbox (mxtoolbox.com) or a similar tool to look up your domain's MX records. Compare the results with what your email hosting provider says they should be.

How to Fix

• Log into your domain registrar's DNS management panel
• Verify your MX records match exactly what your email provider specifies
• Remove any old MX records from a previous provider — conflicting MX records can cause intermittent delivery failures
• Ensure the MX record priority values are correct (lower number = higher priority)
• After making changes, wait up to 48 hours for DNS propagation (though most changes take effect within 1-4 hours)

Problem 2: DNS Propagation Delay

If you recently changed your MX records or switched email providers, DNS propagation delay is likely the cause. DNS changes don't take effect instantly — they need to propagate across name servers worldwide.

How to Check

Use whatsmydns.net to check if your MX records have propagated globally. If some locations show the old records while others show the new ones, propagation is still in progress.

How to Fix

Unfortunately, the only fix is patience. DNS propagation typically takes 1-4 hours but can take up to 48 hours in some cases. While waiting, ensure both your old and new email providers are active so messages aren't lost during the transition.

Problem 3: Full Mailbox

When your mailbox reaches its storage limit, the server will reject new incoming messages. The sender typically receives a bounce-back message saying the mailbox is full.

How to Check

Log into your email account via webmail and check your storage usage. Most providers display this in the dashboard or settings.

How to Fix

• Delete old emails you no longer need, especially those with large attachments
• Empty your trash and spam folders — these count toward your storage quota
• Archive important emails locally using an email client configured with POP3 (which downloads and removes from the server)
• Consider upgrading your plan for more storage if you consistently run out

Providers like Mailbux offer 20 GB of storage on their free plan, which gives most small businesses plenty of room. If you're constantly hitting limits on a provider with less generous allocations, switching may be worthwhile.

Problem 4: Messages Going to Spam

Sometimes email is technically being received — it's just landing in the spam or junk folder instead of the inbox. This is a receiving problem from the user's perspective even though the server is working correctly.

How to Check

Check your spam/junk folder for the missing messages. If they're there, the server is receiving email fine — the spam filter is just being overly aggressive.

How to Fix

• Mark legitimate messages as "not spam" to train the filter
• Add trusted senders to your contacts or allowlist
• Ask your email provider if they offer spam filter sensitivity settings
• If specific senders consistently end up in spam, ask them to check their own SPF, DKIM, and DMARC configuration

Problem 5: Domain Expired or Suspended

If your domain registration has expired, all services associated with it — including email — will stop working. Some registrars provide a grace period, but eventually the domain becomes inaccessible.

How to Check

Use a WHOIS lookup tool to check your domain's registration status and expiration date.

How to Fix

• Renew your domain immediately through your registrar
• Enable auto-renewal to prevent this from happening again
• Make sure the payment method on file with your registrar is current

Problem 6: Email Provider Outage

Even the best email hosting providers occasionally experience outages. If everything on your end looks correct, the problem might be on the provider's side.

How to Check

Visit your email provider's status page or social media channels for outage reports. Try accessing webmail — if you can't log in, the provider may be down.

How to Fix

Wait for the provider to resolve the issue. Most outages are resolved within minutes to a few hours. If outages are frequent, consider switching to a more reliable provider.

Problem 7: Firewall or Security Software Blocking

In some cases, firewall settings, antivirus software, or network security configurations on your server or network can block incoming email connections.

How to Check

If you manage your own email server, check firewall rules for ports 25 (SMTP), 143 (IMAP), and 993 (IMAPS). If you're using a hosted service, this is less likely to be the issue.

How to Fix

• Ensure port 25 is open for incoming SMTP connections on your server
• Check that your antivirus or security software isn't blocking email traffic
• Review any recent changes to firewall rules or security configurations

Problem 8: Catch-All Not Configured

If someone emails an address that doesn't exist on your domain (like a misspelled name), the message will bounce back unless you have a catch-all configured. While not technically a receiving failure, it can cause missed messages.

How to Fix

Set up a catch-all email address that captures all messages sent to non-existent addresses on your domain. Forward these to a monitored mailbox so you can spot legitimate emails sent to misspelled addresses.

Prevention: Monitoring Your Email Health

Rather than waiting for problems to surface, proactively monitor your email configuration:

• Set up uptime monitoring for your MX records using a service like UptimeRobot or MXToolbox monitoring
• Periodically send test emails from external accounts to verify receiving works
• Enable domain auto-renewal to prevent expiration
• Monitor your storage usage and archive or delete old messages before hitting limits
• Keep your DNS records documented so you can quickly verify they're correct if issues arise

Still Having Trouble?

If you've worked through all the troubleshooting steps above and email still isn't arriving, contact your email hosting provider's support team. They can check server-side logs to see exactly what's happening with incoming messages — whether they're being received, rejected, or routed incorrectly.

Looking for reliable email hosting with fewer headaches? Try Mailbux free — enjoy 20 GB of storage, unlimited accounts, and a platform built for dependable business email delivery.