Outgoing mail from Thunderbird to the BT Mail SMTP server

[cj_rupp]

Hi,

I'm getting an intermittent failure using a BT (btinternet.com) account in Mozilla Thunderbird. Most of these instances are under Windows 11 with 128.5.1esr (64-bit) Thunderbird.

What happens is that Thunderbird fails to connect with the SMTP server for outgoing emails with the correct password. This fault is not always present, but recently it has been present more than it has been absent. I have matched all the server setting for BT email that I can find, and I believe the original setting were automatically set by Thunderbird from a template. So, I have to log in to BT email in a browser, copy the message and send it. So, there's nothing wrong with the email, just the link-up between Thunderbird and the SMTP server.

This is the main error message:

Sending of the message failed.
Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'.

I do check, but I haven't been able to find an error there. Hence, I assume that this may not be the true location of the problem.

Any suggestions what I could try next? (Let's assume that a different email client is not a useful answer.)

Thanks for any help. This has been going for several days now.

Cheers,

C. J.

[licquorice]

No idea why you would think suggesting a different client in order to eliminate Thunderbird is not a useful answer, but hey ho.

When the problem occurs, try disconnecting your broadband to force a change of IP address which will possibly result in connecting to a different SMTP server in the farm.

[gg30340]

Are you presently a BT Broadband customer or are you paying for your email through a BT Premium email account?

The correct settings are as per this link but if your email normally works with Thunderbird the settings should be correct.

https://www.bt.com/help/email/manage-email-account/manual-settings/what-are-the-settings-for-outgoin...