There is a special setting in Google accounts to allow "less secure applications" access to your account. If you turn this off, Mozilla Thunderbird won't work to check your e-mail. This is confirmed on this page, where Google says:

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

My question is specially about Thunderbird... what are those security standards that it does not support?

  • The problem also exists with the Mail & Newsgroups component of the Mozilla SeaMonkey suite in the 2.x release series. This is not surprising, as it shares much code with Mozilla Thunderbird. Whether one uses POP or IMAP with SeaMonkey, one needs to turn on the "Allow less secure apps" setting in Gmail for it to work at all.
    – Andrew P.
    Feb 12, 2018 at 19:11

2 Answers 2


Thunderbird doesn't support two factor authentication, so Google has a means of generating a special credential set that can be used with Thunderbird. When configured in this way it works fine with Gmail, but I guess it is less secure than proper TFA.

  • It does however support OAuth in latest versions.
    – grawity
    Jul 26, 2016 at 12:53
  • 1
    That does make sense but just wondering if you have a source with more information. Also, do the mail apps on the phones indeed have 2FA (as mentioned in the Google documentation those mail apps are considered secure)
    – user32421
    Jul 26, 2016 at 14:57

It works for me without enabling less secure applications, although I had to switch from POP to IMAP to get it to work since apparently gmail doesn't support OAuth2 with POP.

First I enabled IMAP in my gmail account. I then enabled 2-step verification in Gmail, which involved giving my phone number (grr). I could, and did, then create an App Password. Back in Thunderbird -- since I didn't discover until later that you can convert a POP account to IMAP -- I deleted and recreated my email account in order to switch to IMAP, using the settings given by Google. Thunderbird auto detected the other settings but if you're setting things up manually the authentication method needs to be OAuth2. Note that the password you enter in the settings is the App Password and not your gmail login password. When Thunderbird first checks for email it will pop up a window to a Google page asking you to enter your login details - this time you enter your normal gmail password. (This popup only comes up the first time you check for email.)

I hope the above helps someone.

  • As of February 2018, Gmail seems to block Mozilla mail clients in both POP and IMAP modes unless "Allow less secure apps" is turned on in Gmail.
    – Andrew P.
    Feb 12, 2018 at 19:13
  • They seem to have gotten rid of the "App Password" option.
    – Wildcard
    Sep 4, 2018 at 19:14

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