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Problems Sending Emails From A Non-PlusNet Domaim

Posts: 1
Registered: ‎18-03-2018

Problems Sending Emails From A Non-PlusNet Domaim



this is a bit of a specific one, but here goes.

We have used our own domain for email purposes for many years - in part so that we do not have to change email address when we change broadband providers. For the sake of this post, let's say that my email address is

We moved to PlusNet in November and since then, have not been able to SEND emails from our own email addresses (incoming POP is fine).

Our setup is quite unusual for a home user - for historical reasons, we use a Microsoft SBS 2011 server at home, with an SMTP send connector/Smart Host to talk to  our ISPs mail servers - so currently, I believe, ?

However, although we have tried this connection with

NO authentication

Basic Authentication

(Using both our primary account say FredBloggs+No23 and a specially set up account FredBloggs+OutgoingMail)

we still get the same results:-

The email does not get sent, with

421 4.2.1 Unable to connect


451 4.4.0 Attempted failover to alternate host,  but that did not succeed.

DNS appears to successfully resolve to the PlusNet mail servers, so I am at a bit of a loss as to where the issue might be.

Therefore, any help or guidance that anybody can give would be greatly appreciated.

Many thanks in advance,



Posts: 11,525
Thanks: 5,128
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Registered: ‎30-06-2016

Re: Problems Sending Emails From A Non-PlusNet Domaim

Are you using the correct outgoing server port? My set up is different to yours but for the record it is set for no authentication and Outgoing Server (SMTP) Port 25.

If that fails try Port 587.

See also here:

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