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Message 1 of 11

unable to send mail to btinternet.com addresses 451 errors

We are trying to send various emails to btinternet.com addresses, but mail is queuing up with the following error.

host mx.bt.lon5.cpcloud.co.uk (65.20.0.49) said: 451 System policy engine error (in reply to end of DATA command): Retry pending

We are sending from clacks.gov.uk addresses

many thanks

David

 

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10 REPLIES 10
Distinguished Sage
Distinguished Sage
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Message 2 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

Do you have  correct SPF and DKIM records in place for your domain?

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656 Views
Message 3 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

Should all be ok as nothing has changed on the mail server, and mail is going to everyone else ok

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Message 4 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

yep, just checked my hotmail account, and dkim and spf record checks passed ok

 

Authentication-Results: spf=pass (sender IP is 194.83.172.62)
smtp.mailfrom=clacks.gov.uk; hotmail.com; dkim=pass (signature was verified)
header.d=clacks.gov.uk;hotmail.com; dmarc=pass action=none
header.from=clacks.gov.uk;
Received-SPF: Pass (protection.outlook.com: domain of clacks.gov.uk designates
194.83.172.62 as permitted sender) receiver=protection.outlook.com;
client-ip=194.83.172.62; helo=smtp.clacks.gov.uk;

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jsplatt
Newbie
630 Views
Message 5 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

My firm is experiencing the same issue with btinternet.com, our mail is sent via Mimecast and we have SPF, DKIM and DMARC records.

Sadly this is not the first time we have experienced these issues with BT.

I have emailed postmaster@btinternet.com in the hope someone can sort it out.

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jsplatt
Newbie
630 Views
Message 6 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

My firm is experiencing the same issue with btinternet.com, our mail is sent via Mimecast and we have SPF, DKIM and DMARC records.

Sadly this is not the first time we have experienced these issues with BT.

I have emailed postmaster@btinternet.com in the hope someone can sort it out.

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jsplatt
Newbie
622 Views
Message 7 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

Scratch that i can't even email the postmaster address.

Sigh

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johnctemple
Aspiring Contributor
573 Views
Message 8 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

I was waiting for an urgent email and it took nearly 6 hours to finally arrive-sent at 1.27 received at 6.56!!! Can we have an explanation please?

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Darren2018
Newbie
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Message 9 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

Any joy or response to this?

We've had the same issue for a couple of weeks now and have SPF, DKIM, DMARC setup.
Emails are being sent to our paying clients but are failing to deliver.

 

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New_To_UK
Aspiring Expert
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Message 10 of 11

Re: unable to send mail to btinternet.com addresses 451 errors

Hi, Just having SPF, DKIM and DMARC does not mean much until its configured correctly. Alongside this, several checks are done on blacklists, anti-spam heuristics etc etc. If you are a commercial sender, there are several tech companies which teach senders on best practices - also there are loads of email deliverability industry forums in the UK. 

Do you get any error messages back when trying to send? this would help close in on your exact issue

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