Email Routing: 451 4.3.0 Internal server error

Clients cannot send mail:

04/20/2022 10:47:25 PM		amir.mx.cloudflare.net [162.159.205.13]	451 4.3.0 Internal server error. FcZYWROalnim
04/20/2022 10:47:24 PM		linda.mx.cloudflare.net [162.159.205.23]	451 4.3.0 Internal server error. X8W1uLGjZpkp
04/20/2022 10:47:24 PM		linda.mx.cloudflare.net [162.159.205.25]	451 4.3.0 Internal server error. NU73vUVNeCl1
04/20/2022 10:47:24 PM		isaac.mx.cloudflare.net [162.159.205.19]	451 4.3.0 Internal server error. GWSBdgcolFfk

Is this a known issue?

1 Like

I’ve got some 4.3.0 issues too, but it’s about receiving emails not sending since yesterday.
4.3.0 Internal server error. lrK7eRVAvIRM

Thanks for the reports. I’m having a look.

1 Like

I’m having the same issues since yesterday

Also had this problem, with incoming emails all being delayed for a long time.
I received a lot of emails this morning, around 6am UTC-4, that were sent last night.
Here’s what the error looks like, in a AWS SES report:

{
    "feedbackId": "010001804ad5e659-5082a239-c17e-4a5d-84c5-c52a0f702cfa-000000",
    "bounceType": "Transient",
    "bounceSubType": "General",
    "bouncedRecipients": [
        {
            "emailAddress": "[email protected]",
            "action": "failed",
            "status": "4.4.7",
            "diagnosticCode": "smtp; 554 4.4.7 Message expired: unable to deliver in 840 minutes.<451 4.3.0 Internal server error. EVrSRJ5Qu896>"
        }
    ],
    "timestamp": "2022-04-21T06:36:13.000Z",
    "remoteMtaIp": "162.159.205.11",
    "reportingMTA": "dns; a8-38.smtp-out.amazonses.com"
}

We identified an issue on our side and reverted a change causing it. Email delivery should be back to normal.

2 Likes

confirmed !

Thanks for the fix, emails are coming in now.

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