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Fix Guide

How to Configure MX Records

MX (Mail Exchange) records tell the internet which servers handle email for your domain. Without MX records, your domain cannot receive email.

How MX Records Work

When someone sends an email to you@yourdomain.com, their mail server needs to find out where to deliver it. It does this by looking up the MX records for yourdomain.com.

  1. 1
    DNS lookup

    Sender's server queries DNS for MX records of your domain.

  2. 2
    Priority sorting

    Records are sorted by priority (lower number = higher priority).

  3. 3
    Connection attempt

    Sender tries the highest priority server first, falling back to others if needed.

  4. 4
    Email delivered

    The mail server accepts the email and places it in your mailbox.

Understanding priority

MX records have a priority value. Lower numbers = higher priority. If you have multiple MX records, mail servers will try them in order of priority.

Example:

10 mail1.example.com (tried first) 20 mail2.example.com (tried if mail1 fails) 30 mail3.example.com (tried if mail2 fails)
Redundancy: Having multiple MX records with different priorities provides redundancy. If your primary mail server is down, emails go to the backup server.

No MX Records Found

Without MX records, mail servers don't know where to deliver email for your domain. Any email sent to your domain will bounce.

How to add MX records

Adding MX records depends on your email provider. You need to:

  1. Get the MX server addresses from your email provider
  2. Add MX records to your domain's DNS
  3. Set the correct priorities

Cloudflare

  1. Go to DNS → Records
  2. Click "Add record"
  3. Type: MX, Name: @ (or your domain)
  4. Mail server: your provider's mail server
  5. Priority: as specified by your provider

Google Domains / Squarespace

  1. Go to DNS → Custom records
  2. Add an MX record
  3. Host: @ (blank or your domain)
  4. Data: priority and mail server

AWS Route 53

  1. Go to Hosted zones → your domain
  2. Create record → Record type: MX
  3. Value: priority + mail server (e.g., "10 mail.example.com")
TTL note: MX record changes can take up to 48 hours to propagate worldwide, though they often take effect within a few hours.

Null MX Record

A null MX record (priority 0, server ".") is a special record defined in RFC 7505 that explicitly states "this domain does not receive email."

A null MX looks like:

0 .

When null MX is correct

A null MX is appropriate for:

  • Domains that only send email (no receiving)
  • Parked or redirect domains
  • Subdomains used only for services (e.g., cdn.example.com)
Why use null MX? It tells senders immediately that email won't be accepted, rather than letting them attempt delivery and fail. This reduces spam and bounce traffic.

When to remove null MX

If your domain should receive email, you need to replace the null MX with actual mail server records. Simply:

  1. Delete the null MX record
  2. Add the correct MX records for your email provider

Common Provider MX Settings

Here are the MX records for popular email providers. Copy these exactly, including priorities.

Google Workspace

1 ASPMX.L.GOOGLE.COM 5 ALT1.ASPMX.L.GOOGLE.COM 5 ALT2.ASPMX.L.GOOGLE.COM 10 ALT3.ASPMX.L.GOOGLE.COM 10 ALT4.ASPMX.L.GOOGLE.COM
Google's official documentation

Microsoft 365

0 yourdomain-com.mail.protection.outlook.com

Replace "yourdomain-com" with your domain (dots become dashes).

Microsoft's official documentation

Zoho Mail

10 mx.zoho.com 20 mx2.zoho.com 50 mx3.zoho.com

Use zoho.eu or zoho.in if your account is in those regions.

Fastmail

10 in1-smtp.messagingengine.com 20 in2-smtp.messagingengine.com

ProtonMail

10 mail.protonmail.ch 20 mailsec.protonmail.ch
Important: Only use MX records from your actual email provider. Using incorrect records will cause emails to be lost or misdirected.

Related Guides

Fix SPF Records

Authorize your mail servers to send

Fix DMARC Records

Configure policies for protection

Verify your changes

After making changes, use our checker to confirm everything is configured correctly.

Check Your Domain