If you encounter this message, it means your SPF record contains a mx mechanism which has one or more Mail Exchange (MX) resource records that contain more than 10 address records - either "A" or "AAAA" resource records. Email sent from this domain will have email delivery problems due to the permerror that will occur due to this error. From RFC 7208 section 4.6.4: The evaluation of each “MX” record MUST NOT result in querying more than 10 address records—either “A” or “AAAA” resource records. If this limit is exceeded, the “mx” mechanism MUST produce a “permerror” result.
To illustrate where this error can occur, please look at the below with particular focus on the mx which means the recipient server should perform a MX Record lookup for that domain to get a list of MX records. Now if any one of those MX records contains > 10 A or AAAA records this error will occur.
v=spf1 mx ip4:1.2.3.4 ~all
When the MX lookup is performed against the domain, it will return a list of MX records. If one of those MX records has 10 combined A & AAAA records the error will be thrown.
Your Email Deliverability is in Jeopardy!
Blacklisting is a sign that you are not actively managing your email deliverability. Other technologies - SPF, DKIM and DMARC are now just as important to get your email placed in the Inbox of your recipients. If you aren’t managing email deliverability, your message may never be heard.
MxToolbox Delivery Center Features:
- Insight into your SPF, DKIM and DMARC configuration to ensure your sending email properly
- DMARC Compliance checks for all of your reported email
- Adaptive Blacklist Monitoring of all your email senders
- Recommendations for improving DMARC compliance and DMARC policies
- Event-based reminders for emergent issues and on-going maintenance
DMARC is a necessity for your business!
Learn More about Email Delivery