2Guides
Fixes for the exact error you're staring at
One page per real DMARC, SPF, and DKIM problem — the query or rejection message, explained, with the exact fix and a free tool to confirm it worked.
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DMARC Checker
Fix Gmail error 550 5.7.26: message does not pass authentication checks
Gmail bounces mail with 550 5.7.26 when SPF and DKIM both fail DMARC alignment. Here's exactly what that means and the record fix that clears it.
Verified Aug 18, 2026
Read the fix → SPF Checker
SPF permerror: too many DNS lookups, and how to fix it
SPF caps you at 10 DNS lookups. Over that limit, receivers treat your entire SPF record as broken. Here's how to count your lookups and cut them back under 10.
Verified Aug 18, 2026
Read the fix →