What should I do

The change that clears the error.

• Fix 550 5.7.26Authenticate the server that sent the message with SPF or DKIM. On direct mail, Google also requires that domain to align with the From header.
• Fix SPF PermErrorA receiver cannot interpret the record. Fix the DNS. A later retry will not clear a permerror the way it can clear a temperror.
• Fix DMARC alignmentMake a passing check use a domain that aligns with the header From. Passing SPF on a different domain does not satisfy DMARC.
• Fix too many SPF lookupsGet the DNS-querying terms down to 10. ip4 and ip6 do not query DNS at evaluation time, so a host written as an address does not spend one of the 10.
• Fix 550 5.7.27Make SPF pass for the host that sent the message. Gmail's bulk-sender rule on this bounce is SPF, not SPF or DKIM.
• Fix 550 5.7.30Make DKIM pass for the message. Gmail's bulk-sender rule on this bounce is DKIM.
• Fix 550 5.7.40Publish a DMARC record that includes a policy. Gmail's bulk-sender rule on this bounce is that record.
• Fix 421 5.7.32Align the header From with a passing SPF or DKIM domain. Gmail names the organizational domain on this bounce.
• Fix 550 5.7.25Give the sending IP a PTR whose forward record points back at that IP. Gmail requires the PTR.
• Fix 550 5.7.29Deliver the message over TLS. Gmail's bulk-sender rule on this bounce is TLS/SSL for SMTP.
• Fix 550 5.7.24Open the published v=spf1 record. Gmail says one or more entries in it are suspicious, and the bounce does not name which.
• Fix 550 5.7.1 IPv6On the IPv6 sending address, publish a PTR whose forward record points back, and authenticate the message. The bounce names both.