Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders

What Does “Temperror” Mean in SPF or DKIM?
If you're seeing temperror in SPF or DKIM results, it means the receiving email server couldn’t complete the authentication check because of a temporary DNS issue. This is not a permanent failure, but it can still impact email delivery.

What Causes It
SPF temperror may happen due to:

• DNS timeout or the DNS server is down
• Too many DNS lookups (limit is 10)
• Invalid or unreachable SPF includes

DKIM temperror may happen due to:

• The public key can’t be retrieved from DNS
• Wrong DKIM selector or malformed DNS record
• DNS provider is temporarily unavailable

Why It Matters

• Emails may be delayed, flagged, or marked as suspicious
• DMARC might fail if both SPF and DKIM checks can't be completed
• Repeated temperrors can damage sender reputation

How to Fix It

• Use tools like MXToolbox or dig to test DNS records
• Keep SPF within the 10-lookup limit
• Verify that DKIM records are correct and accessible
• Choose a reliable DNS provider with low latency

Summary
SPF and DKIM temperrors are temporary issues that stop email authentication from completing. They don’t cause immediate rejection, but they can reduce email deliverability and trust. Fixing them ensures reliable authentication and protects your domain’s reputation.

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