"User is authenticated but not connected" when trying to use ThunderBird as mail client access office365 after confirmed below: Ensure that the user name and password are correct and that the same user name and password run properly on the OUTLOOK client The message can already be Sent and received by the peer end, but the sending will stop forever at 100% copying the message to the Sent folder, and the sent message is synced in Sent mail box in Outlook client. current configuration for Server :

Hi, Please kindly note that: Since thunderbrid is a third-party email client, which we are not very familiar with, I would recommend also posting in thunderbrid support forum if you are having trouble with configuring accounts on thunrderbrid. (Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.) Thanks for your understanding. Here are the steps I configure my test account in thunderbrid(same version 91.8.1(64-bit)): 1.In my test the General.UserAgent.CompatMode.Firefox isn't necessary so I skipped this step 2.select ...>New>Existing Mail Account 3.enter the name and email address(Office 365),leave the password as blank 4.thunderbird auto-detected the settings of Office 365 server It it didn't, you may also configure it manually: 5.After the account is configured, you would be prompted for password, select Cancel: 6.click Account settings locate Server Settings, change Authentication Method to OAuth2 In advanced, uncheck the field of show only subscribed folders locate Outgoing Server(SMTP), also change the Authentication Method to OAuth2 7.back to the main page, click Get messages You would see a Microsoft login pop-up enter the password of your account, if your account have MFA enabled, step forward to authenticate. Once you authenticate successfully, you would see this page: click accept. 8.test send and receive If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

testing IMAP of this mailbox via this link: https://testconnectivity.microsoft.com/tests/O365Imap/input

"User is authenticated but not connected" when trying to use ThunderBird as mail client access office365

Wenshan - Nokia 21

"User is authenticated but not connected" when trying to use ThunderBird as mail client access office365 after confirmed below:

Ensure that the user name and password are correct and that the same user name and password run properly on the OUTLOOK client
The message can already be Sent and received by the peer end, but the sending will stop forever at 100% copying the message to the Sent folder, and the sent message is synced in Sent mail box in Outlook client.
current configuration for Server :

194144-2022-04-19-09-30-06-%E8%B4%A6%E6%88%B7%E8%AE%BE%E7%BD%AE-mozilla-thunderbird.png

Lu Dai-MSFT 28,346 Reputation points

2022-04-19T07:16:27.897+00:00

@YuWenshan-Nokia Thanks for posting in our Q&A. For this issue, it is not related to intune. To get more accurate help, I will add office-exchange tag. Let's wait for the related support engineer involved in this issue. Thanks.
Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2022-04-19T08:22:05.913+00:00

Hi @YuWenshan-Nokia

Are you using the default autodiscover feature in Outlook to connect to Office 365?
If yes, would it work if you configure SMTP and IMAP with the same settings as thunderbrid in Outlook?
Wenshan - Nokia 21 Reputation points

2022-04-19T09:12:45.5+00:00

Hi, KaelYao
thank you for checking this topic
when I use OUTLOOK, it just asked me my mail address then server was configured automatically, and it was done successfully (I did not set server address nor port);
but for Thunderbird client, I got same error message by either automatically configuration and manually doing.

please, as first step, have a check on my configuration (done by manually) pasted in question. Is correct or not?

BR
Wenshan
Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2022-04-19T09:22:40.947+00:00

Hi,
Thanks for the update!

when I use OUTLOOK, it just asked me my mail address then server was configured automatically, and it was done successfully (I did not set server address nor port)

Outlook should be using the autodiscover feature and the protocol is MAPI.

please, as first step, have a check on my configuration (done by manually) pasted in question. Is correct or not?

In the screenshot you are using OAuth2 as the authentication method.
Have you configured it on the Office 365 side?
Reference: Authenticate an IMAP, POP or SMTP connection using OAuth

If not, would you like to use basic authentication (username and password) to access the mailbox in ThunderBird?
Wenshan - Nokia 21 Reputation points

2022-04-19T12:37:06.15+00:00

Hi,
Actually it does not work for all authentication ways, but Oauth2 has closest target, results for your information:
Basic password
Encrypted password
Kerberos / GSSAPI
NTLM
TLS
Oauth2

I remember that one of my colleagues were using Oauth2 for Thunderbird before, but unfortunately he has left company.

as for Authenticate an IMAP, POP or SMTP connection using OAuth, it looks to complex to me due to I am not a technical guy, do you have some simpler instruction or troubleshooting steps?

Accepted answer

Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2022-04-27T07:09:55.953+00:00

Hi,
Please kindly note that:
Since thunderbrid is a third-party email client, which we are not very familiar with, I would recommend also posting in thunderbrid support forum if you are having trouble with configuring accounts on thunrderbrid.
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
Thanks for your understanding.

Here are the steps I configure my test account in thunderbrid(same version 91.8.1(64-bit)):
1.In my test the General.UserAgent.CompatMode.Firefox isn't necessary so I skipped this step

2.select ...>New>Existing Mail Account

3.enter the name and email address(Office 365),leave the password as blank

4.thunderbird auto-detected the settings of Office 365 server

It it didn't, you may also configure it manually:

5.After the account is configured, you would be prompted for password, select Cancel:

6.click Account settings

locate Server Settings, change Authentication Method to OAuth2

In advanced, uncheck the field of show only subscribed folders

locate Outgoing Server(SMTP), also change the Authentication Method to OAuth2

7.back to the main page, click Get messages

You would see a Microsoft login pop-up

enter the password of your account, if your account have MFA enabled, step forward to authenticate.
Once you authenticate successfully, you would see this page:

click accept.

8.test send and receive

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
Please sign in to rate this answer.
Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2022-04-28T09:01:09.053+00:00

Hi @YuWenshan-Nokia

Do suggestions above help?
If any update on this issue, please feel free to post back.
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