Did you have your gmail password saved in Thunderbird? What happens if you change the server to imap.gmail.com?

DocTomJP said

I have used TB for years, with a Hotmail account, and a Gmail account. Suddenly, TB will not get my Gmail emails, giving a message "login to server imap.googlemail.com failed". Hotmail still works fine. I have checked my setup in Gmail, and as far as I can understand, all appears fine. The only clue that have is that I have recently installed Debian on another PC, and got Icedove (Thunderbird by another name) working. Since then I have had a number of messages from Google saying that someone has attempted a login to Gmail from another computer - in fact they were not attempts, but successful logins. I can login to my Gmail account in Gmail with no problems. Can someone assist me please to overcome this problem? DocTom.

This is meant to be a reply to Wayne Merry - sorry if I have got it in the wrong place. Thanks indeed for your rapid response. I tried the suggestions that you made but unfortunately the problem remained. I decided to explore Gmail further, and eventually came across the following : Quote... Google may block sign in attempts from some apps or devices that do not use modern security standards. Since these apps and devices are easier to break into, blocking them helps keep your account safer.

Some examples of apps that do not support the latest security standards include:

The Mail app on your iPhone or iPad with iOS 6 or below The Mail app on your Windows phone preceding the 8.1 release Some Desktop mail clients like Microsoft Outlook and Mozilla Thunderbird. As you see TB is specifically cited.

So I set Gmail to accept the less secure apps - and problem solved!

It remains a mystery to me that this should occur after using TB for so long with no such problems. I suppose it is possible that either TB has decreased its security status, or Gmail has raised its standards, or both.

Now I have a query as to whether my security is at risk in TB or Gmail, and whether anything can be done to mitigate such risk.

But at least for the moment, TB is getting the Gmail messages as previously. DocTom.

Now I have a query as to whether my security is at risk in TB or Gmail

Probably not, but I'd recommend to enable 2-step authentication regardless. In that case you don't need to enable 'less secure apps', but you'd need to create an application specific password for Thunderbird.

Alternatively you can avoid all the hassle with these server settings: Server names imap.googlemail.com smtp.googlemail.com

Choose 'OAuth2' as 'Authentication method' for both, outgoing and incoming server. This makes Thunderbird a 'secure app' again in Google's terms and you can disable 'less secure apps'.

Many thanks Christ1. I elected to try the Authentication Method modification that you recommended.

Unfortunately (in IceDove - Debian version of TB, supposedly almost identical), there is no option to select OAuth2. The box will not accept a typed selection. The only options in the drop down list are :

Normal Password (this is the present selection) Encrypted Password Kerbers/GSSAP1 NTLM TLS Certificate.

In the absense of OAuth2, should I try one of the other options?

Thanks again, DocTom.

there is no option to select OAuth2

You do need Thunderbird 38.0.1 for this. I have no idea about IceDove.

should I try one of the other options?

That is entirely up to you, but I guess you don't have much choice anyway.

DocTomJP said

I have used TB for years, with a Hotmail account, and a Gmail account. Suddenly, TB will not get my Gmail emails, giving a message "login to server imap.googlemail.com failed". Hotmail still works fine. I have checked my setup in Gmail, and as far as I can understand, all appears fine. The only clue that have is that I have recently installed Debian on another PC, and got Icedove (Thunderbird by another name) working. Since then I have had a number of messages from Google saying that someone has attempted a login to Gmail from another computer - in fact they were not attempts, but successful logins. I can login to my Gmail account in Gmail with no problems. Can someone assist me please to overcome this problem? DocTom.

After ca. 12 years unblemished use of Tbird, I'm having the same problem too. Several things happened about the same time which may be a clue.

Tbird was successfully upgraded to 43.x ca. 6 Dec. Gmail logins OK after upgrade.

On 7 Dec created a U Tube account to view a restricted video (inhumane livestock slaughter processes - OK), Google gave no warning this account would override my Gmail config resulting in the new U Tube ID replacing my 13 y.o. Gmail one (BTW can find no way to revert this either).

Gmail via T bird was OK on 7 and 8 Dec, but login today was met with the same issues as the first poster.

I notice the original poster found settings on Gmail web interface to change to a less secure client. I have fruitlessly searched for that page. Please can you provide a lcick this, open that, drop down to there scenario to navigate to the changes.

https://support.google.com/accounts/answer/6010255