A customer says they replied to your invoice, but nothing arrived. Or a vendor receives a bounce that says your domain has no mail server. Before assuming the message was filtered or lost, learn how to check MX records. These public Domain Name System (DNS) records tell other mail systems where to deliver email for your domain.
MX stands for Mail Exchange. An MX record does not send email by itself. It points incoming mail toward the server that accepts it. If that destination is missing, misspelled, outdated, or unavailable, people may not be able to email your business at all.
How to Check MX Records in a Browser
The fastest option is an MX lookup tool. Enter your domain name only, such as `yourcompany.com`. Do not enter `https://`, a web page address, or an email address. The result should show one or more MX records, the hostnames they point to, and usually a priority number.
For example, a result might show:
`10 mail.example-provider.com`
That means mail for your domain should be delivered to `mail.example-provider.com`, with priority 10. The lower the number, the higher the priority. If your domain has two records, such as priority 10 and priority 20, the sending server normally tries the priority 10 destination first. The second record is a backup path if the first one cannot be reached.
A lookup result can also show that no MX record exists. That is a clear problem for a domain that needs to receive email. A few domains are set up to receive mail through a fallback method called an A record, which maps a name directly to an internet address. That arrangement is possible, but it is not the normal choice for a business domain and deserves a closer review.
Check MX Records From Your Computer
If you have access to a command line, you can check the same public DNS information directly. This is useful when you want to confirm what the internet sees rather than what appears inside your DNS provider's control panel.
On Windows, open Command Prompt and enter:
`nslookup -type=mx yourcompany.com`
On macOS or Linux, open Terminal and enter:
`dig MX yourcompany.com`
You may see answers that look technical, but focus on three details: whether an MX record is returned, the hostname listed after it, and the priority number. Save or copy the output before making changes. It gives your IT contact a useful before-and-after record if a DNS correction is needed.
Keep in mind that DNS answers can vary briefly after a change. DNS providers publish a setting called time to live, or TTL, which tells systems how long they may keep a cached answer. A new MX record might appear quickly in one lookup and take longer elsewhere. That is normal propagation behavior, not proof that the correction failed.
What a Healthy MX Record Should Show
The straight answer is that a healthy MX setup points to the mail provider you actually use. If your staff signs in through Microsoft 365, Google Workspace, or another hosted email service, the listed MX hostnames should match that provider's documented setup. If you run your own mail server, they should point to a hostname your organization controls and maintains.
The MX hostname must also resolve to a valid IP address through an A record or AAAA record. An MX record cannot point directly to an IP address. It also should not point to a web page address or a hostname that no longer exists.
More than one MX record is not automatically better. Multiple records can provide redundancy, but only when each destination is intentional and available. An old record left behind from a previous mail provider may route some messages to the wrong place, create intermittent delivery failures, or expose a server you no longer manage.
Common MX Record Problems and the Exact Fix
A missing MX record is the most direct issue. In your DNS provider, add the MX records supplied by your current email provider. Use the exact hostname and priority values they specify. Do not guess based on a similar-looking domain.
An outdated MX record often appears after an email migration. Your business may have moved to a new provider, while DNS still points to the prior one. Remove old MX records only after confirming that every mailbox has been moved and the new provider's MX records are present. Removing records too early can interrupt incoming mail.
A typo in the destination hostname can be just as damaging as a missing record. DNS names are exact. Check each character, including whether the record has an extra copy of your domain appended by the DNS control panel. Some providers automatically add your domain name to a hostname, while others expect a fully qualified domain name. Their interface instructions matter.
Incorrect priority values can cause inconsistent results when you have multiple records. The primary destination should have the lowest number. If an obsolete server has priority 0 and your active provider has priority 10, outside mail systems will try the obsolete server first. Correct the priorities or remove the stale destination.
An MX record that points to a server with no working mail service is a different kind of failure. The DNS answer may look correct, but the destination server may refuse connections or lack the expected mail configuration. This usually requires an SMTP connectivity check. SMTP means Simple Mail Transfer Protocol, the standard process mail servers use to pass messages between one another.
MX Records Are Only One Part of Email Health
MX records control incoming mail. They do not determine whether the email you send reaches the inbox. That distinction matters when you are troubleshooting a sales follow-up, appointment reminder, or customer notice that may have gone to spam.
For outbound email, review your sending authentication and server identity. SPF, or Sender Policy Framework, identifies services allowed to send mail for your domain. DKIM, or DomainKeys Identified Mail, adds a signed identifier that receiving systems can verify. DMARC, or Domain-based Message Authentication, Reporting, and Conformance, tells receiving systems how to handle messages that fail alignment checks.
Other records may be relevant depending on your setup. BIMI, or Brand Indicators for Message Identification, supports approved brand logos in some inboxes. MTA-STS, or Mail Transfer Agent Strict Transport Security, helps require encrypted connections between mail servers. TLS-RPT, or Transport Layer Security Reporting, provides reports about problems with those encrypted connections.
None of these replace an MX record. They address different parts of how email is received, authenticated, and transported. A domain can have excellent SPF, DKIM, and DMARC records yet still fail to receive messages if its MX records are wrong.
Before You Change DNS
Do not edit an MX record just because a lookup displays more than one result. First, verify which email provider currently hosts your mail. Check recent messages received by your team, your provider's admin portal, and any migration notes from your IT support.
Then document the existing records. Note each priority and destination. If your business has shared systems for customer service, invoicing, scanners, website forms, or third-party applications, confirm that the change will not affect those workflows. MX changes primarily affect incoming email, but email system changes often happen alongside broader DNS edits.
If you manage DNS internally, make one planned correction at a time and test afterward. Send messages from an unrelated external address to several mailboxes at your domain. Test both new messages and replies. Check that the messages arrive in the intended mailbox, not merely that they avoid a bounce.
If your DNS is controlled by a former employee, web developer, or outside provider, pause before making assumptions. You need access to the authoritative DNS zone - the active set of records used by the internet. Editing a parked domain, an old registrar account, or a copied DNS zone will not fix the live problem.
When the fix involves DNS access you do not control, an email migration, or a mail server that will not accept SMTP connections, hand it to a qualified administrator. These changes are manageable, but a wrong record can stop incoming email for the whole organization.
For a clear view of your MX records alongside authentication, network, and reputation checks, run MailArrive's free email health check and use the Report Card to identify the next exact fix.