Why wouldn’t Thunderbird send my emails when I was abroad?

Q  Recently I was in La Palma in the Canary Islands and I took my netbook in the hope of getting online. I managed to connect to the web easily enough and was also able to receive emails.

However, I was not able to send messages. Instead, my email program (Thunderbird) repeatedly displayed the following error message: “Sending of message failed. This message could not be sent because connecting to SMTP server pop3.tiscali.co.uk failed. The server may be unavailable or is refusing SMTP connections.”

Unable to resolve this, I switched to the webmail service from by my internet service provider (ISP) and was then able to send emails without problem. When I returned home, everything was fine once more: Thunderbird would receive and send emails. Is there a problem using Thunderbird abroad?
B Harrington

A  This has nothing to do with Thunderbird per se. Rather, it is because your ISP is not allowing email messages to be sent via what’s known as its SMTP server (essentially this is a computer that collects messages you want to send and then distributes them across the internet).

There’s one of three likely reasons for this but to understand two of them, it’s important to realise that few ISPs are happy to let just any Tom, Dick or Harry send messages via their SMTP servers – it would be an open invitation for spammers to go about their business unchecked.

As a result, many SMTP servers require users to protect their identity themselves in some way. This can be done via submission of an account username and password or by being directly connected to the ISP’s network – or both.

You didn’t go into detail but the thrust of your email was that you didn’t change any settings between leaving home and arriving in La Palma, so we think that either or both of these are the likely cause here.

In other words, whether or not the ISP’s SMTP server requires username and password authentication (more on that in a moment), when emailing from home your netbook is effectively directly connected to the SMTP server (in fact it’s the modem or router that is connected but it makes no odds – the SMTP server ‘sees’ the email data as coming from a device that’s directly connected to the ISP’s network).

When you disconnect from your home network that direct-authentication avenue disappears, leaving just the username and password option.

The trouble is, plenty of ISPs will refuse attempts to use their SMTP server unless the sending device is connected to the same network, even if the correct account username and password are supplied by the email program. This would explain why everything worked fine once you returned home.

However, eagle-eyed readers may have noticed that one small mystery remains: the error message you detailed suggests that the SMTP server is pop3.tiscali.co.uk. This is one of Tiscali’s (now Talktalk’s) legacy POP (incoming) mail servers; the corresponding SMTP server is smtp.tiscali.co.uk.

In fact, we think this is a simple naming error that occurred when setting up Thunderbird. You didn’t tell us the version of Thunderbird you’re using but if you visit the Accounts Settings dialogue (from the Tools menu) you should easily enough be able to find the SMTP server settings – its under ‘Outgoing Server (SMTP)’ in version 3, for example.

Now click to highlight the server labelled Default then click Edit. In the box that appears, our guess is that the Server Name will be correct (smtp.tiscali.co.uk) but that the Description will read ‘pop3.tiscali.co.uk’.

This doesn’t matter as such, because it’s just a label, but it can lead to obvious confusion – so we would suggest changing it.

As well, from here you can specify different or additional SMTP servers, which might be helpful the next time you head abroad. If you have a Google account, for example, then it’s possible to use its SMTP server from anywhere – only the username and password are required for authentication.

To find out how to set this up in the various versions of Thunderbird, visit Mozilla’s support page.