In reply to a post by Oliver341:

In reply to a post by Pheasant:

Does the OP's version of Outlook actually support the newer version of TLS 1.2?

Outlook 2003 predates TLS 1.2 by several years, and it was not backported to Outlook 2003 as far as I know.

Had a quick search and as I understand it, Windows 10 should automatically set the default secure client-server secure protocol as TLS 1.2 when using using WinHTTP. There are workarounds and a KB fix for some earlier versions of Windows, but I dont think that applies here.

https://docs.microsoft.com/en-us/security/engineerin...

But Outlook 2003 as you say is simply too old to take advantage of this - so any server SMTP connections that need TLS 1.1/1.2 will just fail.

Edited by Pheasant (Sat 11-Jun-22 18:31:57)

In reply to a post by Andrew_W:

So how is it that it stopped working three days ago?!!

If the isp is disabling deprecated tls protocols, this would explain the change.

If you use Avast anti-virus program there is some bug in the most recent version.

I think someone suggested disabling the mail shield to see if it works.

In reply to a post by bowdon:

If you use Avast anti-virus program there is some bug in the most recent version.

I think someone suggested disabling the mail shield to see if it works.

Tried that, no change.

In reply to a post by Pheasant:

Ah shame about the weather, quite balmy here.

Other than the port number for SMTP - are you using the current server names in the mail client settings, as per the guide here?

In Thunderbird have you enabled STARTTLS in connection security for the outgoing server?

STARTTLS enabled in TBird and settings are as per Idnet guide in Outlook.

One point, I switched off the router overnight and when I switched back on this morning I was able to send about five test emails from Outlook until it failed again. Tried the same off/on trick again but no good!

If you ping the mail server, do you get any timeouts?

In reply to a post by Pheasant:

If you ping the mail server, do you get any timeouts?

On my Windows PC if I ping smtp.idnet.com it just says "request timed out" straight away.

If I ping mail.idnet.com I get an immediate response (18ms) same with bbc.co.uk for example.

I have now fired up my Linux Mint PC. Cannot send emails with that either and no response at all from smtp.idnet.com but do get a response from mail.idnet.com and the BBC.

WHY??????????

Well at least we now know it not a TLS issue but a network issue.

Possibly some sort of DNS issue on your Netgear router. Can you ping successfully 212.69.40.22 from your machines?

In reply to a post by Pheasant:

Possibly some sort of DNS issue on your Netgear router. Can you ping successfully 212.69.40.22 from your machines?

I could do about an hour ago but not now. Not changed anything here on either PC.