How To Create SPF Records To Avoid SPF Lookup Limit Errors? https://www.duocircle.com/content/spf-too-many-dns-lookups/spf-lookup-limit
SPF Record Checker https://easydmarc.com/tools/spf-lookup?domain=mercari.com
1. whois
Valid Lookup count 11/10 mercari.com 11 LOOKUPS (9 main, 2 nested)
include 先の include も含めてカウントする。