DIAGNOSTIC ERROR
SPF PermError: 10-Lookup Limit Exceeded
Why your emails are suddenly bouncing, and how to fix it.
Are your emails suddenly bouncing? Jump straight to our free diagnostic tool to see if your domain is hitting the 10-lookup limit, or read below to learn how to fix it.
Free Email Diagnostic ScannerThe Problem
If you're seeing a "PermError" or your emails are suddenly routing to spam folders at Microsoft 365 and Gmail, you have likely exceeded the strict SPF 10-lookup limit imposed by RFC 7208.
The Physics of the Error
Your SPF record isn't just a text string; it's a set of instructions. Every time you add a vendor (like include:spf.protection.outlook.com or include:_spf.google.com), the receiving server has to perform a DNS lookup to resolve it.
To prevent infinite loops and denial-of-service attacks, the internet enforces a hard limit of 10 nested DNS lookups per SPF check. Once your record requires 11 lookups, Microsoft and Google stop reading it. It fails completely. In the eyes of their spam filters, your domain is completely unauthenticated.
The Solution
You cannot simply add more include statements. You must either flatten your SPF record by manually resolving the IP addresses (which requires constant, dangerous maintenance), or use an active SPF macroeconomic flattening service.
Related Email Authentication Issues
When SPF "PermErrors" Require Professional Help
Resolving an SPF PermError usually requires careful DNS record flattening to stay under the 10-lookup limit—a frustrating process that can easily break your email flow. Let our digital identity experts correctly map and flatten your DNS records for a flat rate of $250.
