65.20.50.207 - SMTP Connection Error: dial tcp :0->10.0.44.50:2525: bind: address already in use

[jshovelt]

Hi all,

Over the past 24 hours our clients are seeing this error message when sending to BT addresses through our web application. 

65.20.50.207 - SMTP Connection Error: dial tcp :0->10.0.44.50:2525: bind: address already in use

Does anyone know what it means?

We use a third-party mail host (based in India) and we've had so many problems sending to BT over the past year that the BT Postmaster has kindly whitelisted our sending IP address. So I'm really stumped by this one!

Any help would be much appreciated, thank you.

[Crimliar]

I'm very much prepared to be wrong on this!

10.x.x.x is not a public IP range, so it can be routed to from outside the private network hosting the server.  Which would mean that your clients can't access the server using your web application.  If I'm right on this, then there is an error in the code that creates the server address in the web app!

[jshovelt]

I am now getting this error message instead:

65.20.50.207 - SMTP Connection Error: <nil>

Only about 10% of my emails are showing as delivered, the rest are soft bounced and the latest bounce message,  is:

65.20.50.207 - SMTP Connection Error: <nil>

which was first seen at 02/12/2024 16:20

I also had one instance of this message:

65.20.50.207 - SMTP Connection Error: 421 btprdrgi019.btinternet.com Service not available

but 2239 bounces since then have just read:

65.20.50.207 - SMTP Connection Error: <nil>

I know the IP address 65.20.50.207 is correct for BT as I have performed nslookup on mx btinternet.com

Does anyone know what this means? Is BT known to be having problems receiving email recently?

Thank you for your help.

[licquorice]

SMTP is a send protocol, not a receive protocol. Are you trying to send mail via BTs servers?

[jshovelt]

No. My clients send emails to their members using our web application. All the emails are sent through our mail host (third-party company). Accross our entire client base we send an average of 13000 emails per day. We are only seeing a problem with recipients with btinternet email addresses. The latest spate of issues started last week, on 27th November. We started getting bounces saying:

65.20.50.207 - SMTP Connection Error: dial tcp :0->10.0.44.50:2525: bind: address already in use

We then started seeing this:

65.20.50.207 - Smtp connection nil

Then this:

65.20.50.207 - "422 We have protected our customers by limiting the emails coming from this source as this could potentially be SPAM. If you believe this to be in error please contact your email provider.rn" 

and this:

65.20.50.207 - "422-Too many messages from 175.158.66.155 on 2024/12/02 04:44:17 GMT. We have received a high volume of emails in a short space of time from this IP address. You may have been affected unknowingly through your email provider.rn"

Which I thought was probably because the messages had been backed up due to previous errors.

Now we are seeing this:

65.20.50.207 - SMTP Connection Error: <nil>

[licquorice]

I obviously have no idea how your web application works, but an SMTP error is a send error not a receive error.