If your provider changed their server setting requirement then you need to make those changes in the Thunderbird settings. Contact your provider for the correct server settings and make the necessary changes in Thunderbird.

Do you mean you applied 2-step or 2-factor verification to your icloud account? If so, you should create an app-specific password and enter it in TB (after you delete the old password in Options/Security/Passwords/Saved Passwords).

Hi, I have the same problem. Did useing the app-specific password solve it for you? Thunderbird doesn't accept my old password, nor the app-specific passwords I have tried...

The app specific password resolved this issue thanks

The app specific password resolved this issue thanks

Here is a detailed response for resolving all these issues with Apple email accounts with non Apple apps or email clients.

There are many, perhaps hundreds, of posts complaining about folks being unable to login to iCloud.com or me.com using mostly third party apps like Microsoft Outlook, Mozilla Thunderbird, or other mail, contacts, and calendar services not provided by Apple. I recently spent hours reading through these posts and their suggestions all of which did not work for me. The reason for these problems is NOT Thunderbird or other apps. It is because Apple made changes some months back but apparently told nobody.

After successfully contacting an extremely high level support tech at Apple. I am happy to provide my fellow sufferers with the definitive answer. Follow this, and you will have no more issue with Thunderbird, Outlook, and Android email app. Worked for me 1st time on FIVE different apps.

So the deal is you MUST use and configure your Apple ID as follows:

1. Set up two-factor authentication for your Apple ID. This is NOT 2 step authentication! Two-factor authentication is a new service built directly into iOS, macOS, tvOS, watchOS, and Apple’s web sites. It uses different methods to trust devices and deliver verification codes, and offers a more streamlined user experience. Two-factor authentication is required in order to use certain features that require improved security.

• • • To set up two-factor authentication, you must do so from any Apple product that is configured with iOS 10.2 or later or OS X El Capitan or later

2. Once this has been done, you need to generate app-specific passwords. You will generate one password for each application or client (Thunderbird, etc) that you use. Sounds difficult. It is not. I generated several and INSTANTLY I was able to successfully configure all my problem apps and clients the FIRST TIME.

So where to start? Here are the links that you will need. So long as you are using iOS 10.2 or later or OS X El Capitan or later, this is very easy.

A. Read this first about availability of two-factor authentication for Apple ID: https://support.apple.com/en-us/HT205075

B. Next, read about app specific passwords and how to generate them here: https://support.apple.com/en-us/HT204397

C. Now read about Two-factor authentication for your Apple ID. Follow the instructions given. You may set up Two-factor authentication for Apple ID from any device using iOS 10.2 or later or OS X El Capitan or later.

Follow A,B and C and configure your email on any device (Android etc, or any email client, i.e. Thunderbird and all others.

i've already done this twice. it does not solve the problem, sorry.

Could you please post the format, NOT the actual password that are using? i.e. how many characters and how arranged,

xyza-abce-hjkq-poiu

(sixteen random letters in four groups of four, each group separated by hyphens)

ok... that is the correct format.

Only two more suggestions. Make sure you are using the current version of Tbird and DELETE all prior instances of your .me account. You ARE using .ME and not .iCloud right?

Now try it again using tBirds DEFAULT config. i.e. change nothing. No changing of login names, servers. nothing. Only the defaults entered by Tbird

I just did a new config on Tbird on a new computer and as always, it worked perfectly first time.

If you still have issues... sorry. Not much more I can do. Of course the best is to delete tBird and start again with fresh copy.

i got this logging report for the other thread; it appears to be an apple problem:

A kind soul (nobody from this thread though) posted log data about the problem. This is the current state of affairs:

Looking closer at the log for imap.mail.me.com it appears that tb is doing the right thing. When a mailbox authenticate response contains XSENDER capability, tb includes the XSENDER in the "UID FETCH" request. For mailboxes that do not contain XSENDER capability in the authenticate response there is *no* added XSENDER flag in the "UID FETCH" request to the server.

The problem occurs when the server reports XSENDER capability for the connected mailbox but then rejects the "UID FETCH X:Y (XSENDER ...)" request. For example, the connection for "Sent" mailbox reports the following capability:

[Unnamed thread 0x7f74f97771a0]: I/IMAP 0x7f74dfc11800:imap.mail.me.com:NA:CreateNewLineFromSocket: 1 OK [CAPABILITY XAPPLEPUSHSERVICE IMAP4 IMAP4rev1 ACL RIGHTS=tekx QUOTA LITERAL+ NAMESPACE UIDPLUS CHILDREN BINARY UNSELECT SORT CATENATE URLAUTH LANGUAGE ESEARCH ESORT THREAD=ORDEREDSUBJECT THREAD=REFERENCES CONDSTORE ENABLE QRESYNC CONTEXT=SEARCH CONTEXT=SORT WITHIN SASL-IR SEARCHRES METADATA ID XSENDER X-SUN-SORT ANNOTATE-EXPERIMENT-1 X-UNAUTHENTICATE X-SUN-IMAP XUM1 IDLE] User gd.smth logged

Then on the same mailbox the following UID FETCH occurs with an error response from the server:

[Unnamed thread 0x7f74f97771a0]: I/IMAP 0x7f74dfc11800:imap.mail.me.com:S-Sent:SendData: 8 UID fetch 1,2:3 (XSENDER UID RFC822.SIZE BODY.PEEK[]) [Unnamed thread 0x7f74f97771a0]: D/IMAP ReadNextLine [stream=0x7f74e03952c0 nb=43 needmore=0] [Unnamed thread 0x7f74f97771a0]: I/IMAP 0x7f74dfc11800:imap.mail.me.com:S-Sent:CreateNewLineFromSocket: 8 BAD Invalid UID Fetch attribute XSENDER

This information should be reported to Apple so they can fix their server.

Why are people advising on 2factor authentication for thunderbird, they must use 2step authentication only.

see my post to resolve issue.

https://support.mozilla.org/en-US/questions/1174729