SPF is one vendor away from breaking
ATTENTIONWhat it means
Your record already costs N of the 10 permitted DNS lookups. The next tool your team signs up for pushes SPF into permanent error, and nothing will warn you.
How to fix it
Make room now: remove vendors you no longer use, or flatten a stable include into its ip4:/ip6: ranges.
Check your own domain
This page describes the condition. To find out whether your domain has it, run the SPF test or the full checkup, which examines every record at once.
Understand it properly
This page covers one condition. For the whole picture, What is SPF, and the ten-lookup limit, or start at the Health Library.
Where this comes from
We judge this against RFC 7208 section 4.6.4. Every finding on this site cites the specification behind it so you can check the work rather than take our word for it.
Other SPF conditions
SPF_LOOKUP_APPROACHING_LIMIT
Every fix on this site is yours to implement. If you would rather someone did it, I take this work directly.