Email DNS error checker: what SPF, MX and DMARC errors mean and how to fix them
In short: Explains and fixes multiple SPF records, too many SPF lookups, "MX record doesn't have 2 fields", MX not found, MX pointing at an IP or with the domain doubled, multiple DMARC records, p=none and long DKIM keys. Limit: DKIM needs a selector, so a domain check doesn't read DKIM; use the DKIM checker or selector finder.
An email DNS error checker explains the error messages DNS hosts, scanners and email providers show for SPF, MX, DMARC and DKIM, and says what to change. Paste the message, such as "SPF validation error" or "MX record doesn't have 2 fields", or enter your domain to read its live records for the same mistakes: two SPF records, too many lookups, two DMARC records.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Sample result
"MX record doesn't have 2 fields": Route 53 wants priority and host in one value, 1 smtp.google.com.
- Domain
- northwind.example
- SPF
- Two records
- DMARC
- p=none
What this means for you
Paste any SPF, MX or DMARC error for what it means and the fix, or enter a domain to read its live records.
- Paste the error or a domain
- Plain meaning of each error
- The exact fix
- Live MX, SPF and DMARC
- SPF
- MX
- DMARC
By SimpleVerifier Team · Last updated
DNS fixed. How do I make sure the list doesn't cause the next problem?
- Export the list you're about to send to as a CSV.
- Upload it on the verify page; the first checks are free.
- Send to the valid rows only.
How do I fix an SPF, MX or DMARC error?
- Paste the error message exactly as shown, or enter your domain instead.
- Press Explain and fix. A message is matched in your browser; a domain's MX, SPF and DMARC are looked up live.
- Read what each problem means and the fix, then make the change at your DNS host.
- Enter the domain again after the change to confirm the problem is gone.
Example
- You enter
- The error
MX record doesn't have 2 fields, then the domainnorthwind.example. - You get
- The message: Route 53 wants priority and host in one value, such as
1 smtp.google.com. The domain: two SPF records (merge them into one) and DMARC at p=none, with the live MX, SPF and DMARC records shown. - Limits
- Error text is matched in your browser; domain lookups are ten a minute per visitor.
What does "SPF validation error" mean?
It means the checker couldn't read your SPF record as valid. The usual causes are two TXT records starting with v=spf1 (a permanent error under RFC 7208), more than 10 DNS lookups across the record and its includes, a typo such as include without its colon, or an all that isn't the last term.
Fix it by publishing one record: a single v=spf1, an include for each service that sends as you, and ~all or -all at the end. The SPF record merger combines two records into one.
What does "MX record doesn't have 2 fields" mean?
Amazon Route 53 and some other DNS hosts take an MX value as two fields in one line, priority then host: 1 smtp.google.com. Entering only the host gives this error. Put each mail server on its own line in the same record.
Other MX errors this checks for: no MX at all, an MX that is an IP address (not allowed by RFC 5321), and a host with your domain appended (smtp.google.com.yourdomain.com), which happens when a DNS host adds the zone to a value saved without a trailing dot.
Can you have multiple DMARC records?
No. RFC 7489 says that when _dmarc returns more than one DMARC record, receivers ignore DMARC for the domain. Keep one record and put every report address in its rua= tag, separated by commas.
Who uses this tool, and for what?
- Small businesses
- Make sense of a registrar's or scanner's error message without reading the RFCs.
- Cold emailers
- Catch two SPF records or a doubled MX host on a new sending domain before the first campaign.
- MSPs
- Explain a client's security-scan finding and the exact record change in one place.
What can’t this tool tell you?
- DKIM needs a selector, so a domain check doesn't read DKIM; use the DKIM checker or selector finder.
- Error text is matched against common messages; a message we don't recognise gets no guess.
- A CNAME behind an MX host isn't followed here; the CNAME lookup shows it.
- It reads public DNS, which can lag a change until the old record's TTL runs out.
Common questions
- What does SPF validation error mean?
- The SPF record couldn't be read as valid: usually two SPF records, more than 10 lookups, a typo, or an all that isn't last.
- Can I have two SPF records?
- No. Two v=spf1 records is a permanent error and SPF fails. Merge them into one.
- Can you have multiple DMARC records?
- No. Receivers ignore DMARC when there's more than one. Keep one and list every report address in rua=.
- What does MX record not found mean?
- The domain has no MX records, so mail to it can't be delivered normally. Add your mail provider's MX records.
- Why does my DKIM record get cut off?
- A 2048-bit key is longer than one 255-character DNS string. Split it into two quoted strings in one record, or use the provider's CNAME.
Sources
You audited one domain. Cold outreach means thousands.
This tool checks a domain you type in. It will not tell you which addresses at that domain are real.
- Bulk mailbox verification with real SMTP checks
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- Website enrichment for emails, owner names and socials
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