Forms emailed by Form Builder are rejected by Gmail. Reason: "Sender not Verified"

CapnCAVU — Sat, 20 Sep 2025 08:07:21 GMT

For your reference this is Case #: 86642289

Subject: My customers fill out an online form on my site. When done and submitted, the form is sent to me...
Questions or Feedback: My customers fill out an online form on my site. When done and submitted, the form is sent to me AND a copy to the customer. My copy of the form arrives fine in my email. But my customer's copy is refused by Google Daemon - message says the Sender is not verified. Fail Message is below:

The original message was received at Sat, 11 Nov 2023 14:40:57 -0500 from ip-10-103-52-2.ec2.internal [10.103.52.2]

----- The following addresses had permanent fatal errors ----- <ashleilachelle@gmail.com>
(reason: 550-5.7.26 This mail has been blocked because the sender is unauthenticated.)

----- Transcript of session follows ----- ... while talking to gmail-smtp-in.l.google.com.:
>>> DATA
<<< 550-5.7.26 This mail has been blocked because the sender is unauthenticated.
<<< 550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
<<< 550-5.7.26
<<< 550-5.7.26 Authentication results:
<<< 550-5.7.26 DKIM = did not pass
<<< 550-5.7.26 SPF [gmail.com] with ip: [34.236.172.26] = did not pass <<< 550-5.7.26 <<< 550-5.7.26 To mitigate this issue, please visit Gmail's authentication guide <<< 550-5.7.26 for instructions on setting up authentication:
<<< 550 5.7.26 https://support.google.com/mail/answer/81126#authentication f10-20020ac87f0a000000b00417cd1d2a6bsi1860588qtk.136 - gsmtp
554 5.0.0 Service unavailable

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thread Forms emailed by Form Builder are rejected by Gmail. Reason: "Sender not Verified" in Payments Troubleshooting

Forms emailed by Form Builder are rejected by Gmail. Reason: "Sender not Verified"