What the MX checker shows
When someone emails you@example.com, their mail server looks up the MX (mail exchanger) records for example.com to find out where to deliver the message. Enter a domain and the checker lists those records: each mail host and its priority, with the time of the check. If there are none, it says "No MX records found for this domain".
The checker reads the published records only. It doesn't send a test message or connect to the mail servers, so a correct result means your email is routed to the right place, not that the mail server is working. You get 5 free checks without an account, shared across all the UpMonix tools, and 5 more with your email address.
Reading priorities
Each MX record has a number. Lower numbers are tried first. A result might look like this:
| Priority | Mail host | What it means |
|---|---|---|
| 10 | mx1.example-mail.net |
The main server; tried first |
| 20 | mx2.example-mail.net |
A backup, used if the first can't be reached |
If two records share the same number, sending servers spread mail between them. The numbers themselves don't matter, only their order: 10 and 20 work the same as 1 and 5. What matters is that every host listed belongs to the email service you use today.
Common MX problems and how to fix them
The old host's MX was left behind after a migration
You moved to a new email provider and added its MX records, but the old ones are still there. Some mail now goes to a mailbox nobody checks. It's easy to miss because most email still arrives. Remove every MX record that doesn't belong to your current provider.
MX pointing to a CNAME
An MX record must point to a hostname that has its own address record, not to an alias (RFC 2181, section 10.3). Some sending servers cope with an alias and others refuse, so the fault looks random. Point the MX at the real mail hostname your provider gives you.
No MX records at all
If a domain has no MX records, sending servers fall back to the domain's A record and try to deliver there (RFC 5321, section 5.1). That's usually your web server, which probably doesn't accept email. If the domain should receive mail, add the MX records from your email provider. If it should never receive mail, ask your DNS host about a "null MX" record (RFC 7505), which tells senders so.
Typos in the hostname
A single wrong letter sends mail nowhere. Also watch for the trailing-dot problem: in some DNS panels, entering a hostname without the final dot makes the system add your own domain, giving something like mail.provider.com.example.com. Compare each host in the result, character by character, with your provider's instructions.
MX vs SPF, DKIM and DMARC
MX records control incoming mail: where messages to you are delivered. SPF, DKIM and DMARC protect outgoing mail: they help other servers check that email claiming to be from your domain really is. All three are published as TXT records, not MX records. You can see your SPF record with our DNS checker.
Moving to Microsoft 365 or Google Workspace? Use the exact MX values shown in your provider's admin console or setup guide. They can differ from one account to another, so don't copy them from someone else's domain.
When a one-off check isn't enough
Email fails quietly. Nobody sees an error page, the enquiries simply stop arriving. UpMonix monitors your MX records and mail server connectivity and emails you when something changes or stops responding, so you hear about it before a customer tells you they've been bouncing.
MX monitoring is included on every plan. The Free plan is free forever for one domain, with no credit card needed. Paid plans add more monitors, faster checks and more alert channels: see pricing or see everything UpMonix monitors.
FAQ
What is an MX record?
An MX (mail exchanger) record is a DNS record that tells other mail servers where to deliver email for your domain. Each record names a mail server and a priority number; lower numbers are tried first. Without correct MX records, messages sent to your addresses can be delayed, bounced or delivered to the wrong place.
Why am I not receiving email?
Start with the MX records. If they point to an old provider, contain a typo or are missing, mail won't reach you. If the records look right, the problem is more likely the mailbox itself: it could be full, a spam filter rule or a forwarding setting. Your email provider's admin panel usually shows rejected or quarantined messages.
What MX records should I use for Microsoft 365 or Google Workspace?
Use the values your provider gives you in its admin console or official setup guide. Microsoft 365 generally shows a hostname specific to your domain, and Google publishes its own list. Enter them exactly, remove any old MX records, then run this checker to confirm only the new hosts appear.
Will UpMonix alert me if my MX records change?
Yes. MX monitoring is included on every UpMonix plan, including Free, which is free forever for one domain. UpMonix checks that your MX records are present and your mail server responds, and emails you when something changes, so a mistaken edit or an expired account doesn't go unnoticed for days.
Is this tool free?
Yes. You can run 5 checks without an account, shared across all the UpMonix tools, and add your email address to unlock 5 more. Cookies must be enabled. If you'd like your mail setup watched continuously, create a free UpMonix account for one domain.