All Products Community Forum

Hi. I use Thunderbird Android 17.0 on my phone and tablet. Everything is great on the phone.

On the tablet, unified inbox worked fine until two days ago. Now, no email goes into the unified inbox and I have to open accounts individually to see email. The unified inbox still shows, but the last email in there is from two days ago. I did not change any settings and berichten that the checkbox is checked to show the unify inbox.

What cohort have caused this and how can I fix it?

Hello! After I was on vacation for about 2 months, I suddenly couldn't receive any more emails. "Login to the server imap... failed." Why this - and what can I do? Thanks!

Can get(POP3), but can not send emails to a newly created personal outlook.com account.

the following error occurs when trying to send mail: Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)

all my setting are correct per thunderbird and microsoft:

  (smtp-mail.outlook.com, port 587,  STARTTLS, OAUTH2, xxxxx@outlook.com)

thunderbird error log file contains the following: . . . mailnews.smtp: S: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]

SmtpClient.sys.mjs:452:17 mailnews.smtp: Command failed: 535 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [CH5P220CA0005.NAMP220.PROD.OUTLOOK.COM 2026-02-28T23:29:21.878Z 08DE7703D4D1982A]; currentAction=_actionAUTH_XOAUTH2 SmtpClient.sys.mjs:578:19 mailnews.smtp: Error during AUTH XOAUTH2, sending empty response . . .

Based on my understanding its seems thunderbird is using SMTP AUTH instead of OAUTH2 as required for newer personal outlook.com accounts. Is my assessment correct? If so, is there a fix?

thunderbird is not sending or receiving email to a particular legitimate email address; never had this problem in the past--it's just one particular email--please stop blocking it; @inreach. garmin.com

thunderbird is not sending or receiving email to a particular legitimate email address; never had this problem in the past--it's just one particular email--please stop blocking it; @inreach.garmin.com

When checking for new email a pop asking for the username and password of the for the email server. Also when a separate email client is downloaded. This only happens when. using a mac book pro. No problem when. using Ubuntu.

Voilà le message d'erreur quand je veux envoyer un mail ou transferer un mail L’envoi du message a échoué. Une erreur est survenue lors de l’envoi de l’e-mail. Le serveur a répondu : DfERwzp30T90v Mail rejete. Identifiant et adresse mail appartiennent a 2 utilisateurs differents. OFR203_528 [528]. Veuillez vérifier le message et essayer à nouveau. C'est récurrent et l 'adresse n' appartient pas 2 utilisateurs différents Je suis obligée d 'envoyer de mon portable où je n'ai pas de soucis Cordialement

Hi. Since the Thunderbird update in March/2026, my Bell sympatico.ca email is no longer able to send emails out through Thunderbird. No error messages but emails never get to destination (I tried sending to myself on both gmail and sympatico accounts). I receive emails without issue. I tested the sympatico from the web or my iPhone and it works. Seems something changed in T-bird back in March?

I validated the Outgoing SMTP server settings and all seems OK (See attached file for screenshot of settings). Any idea why and what changed to cause this?

Tx, Robert Ziwani

When ever I try to send an email list I get the reply below. Usedto work waht am I doing wrong??? HELP Sending of the message failed. An error occurred while sending mail. The mail server responded: <Reminder>: recipient address must contain a domain. Please check the message recipient "Reminder" and try again

Regards John Dobson.

will not download -- "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox"

突然、どこにもメールの送信ができなくなってしまいました。 受信はできます。 KDDIを使っていますが、問い合わせしましたが、サーバーに問題ありません。 Webメールでは送信できます。 Thunderbird側の問題のようです。 添付のようなメッセージが表示されエラーになってしまいます。 解決策を教えてください。

Suddenly, I can no longer send emails anywhere. I can still receive emails. I use KDDI, and I contacted them, but they said there are no issues with their servers. I can send emails using webmail. It seems to be an issue with Thunderbird. The message shown in the attachment appears, and I get an error. Please let me know how to fix this.

I installed Thunderbird on a new Motorola Razr running Android 15. It worked just fine for a few days, but now will not download any new emails (GMail on the same phone is working fine). I have two accounts installed. One (much smaller) seems to be working fine, while the other is only partially working. Namely, I can only see emails from Monday or earlier (today is Thursday).

If I use my desktop to delete one of the older messages that is displayed on the phone, it will be removed from the phone the next time I swipe down and have it refresh the inbox. If I use the desktop to update the read/unread status of an email that does appear one the phone, that is not updated when I refresh the phone.

It is a recently added account, is it possible that the device is just downloading older messages and is backed up? I don't know where or how I could access the activity monitor (or whatever the proper name is) to see what the program is or is not doing.

Changed p/w as solution no help Today for some reason Thunderbird won`t download from xfinity. Worked well yesterday,been on phone with xfinity about 1 hr. or so. restart pc no help

host eig-east.smtp.a.cloudfilter.net [18.215.58.191]

   SMTP error from remote mail server after end of data:
   550 Connection Rejected - see http://www.spamhaus.org/query/ip/162.241.253.30 AUP#BL

I am having a configuration problem on my Android phone, configure it from the application installed on my Windows laptop. I receive my emails but they are periodically completely deleted during message synchronization. how to resolve this malfunction? THANKS

Mein Betriebsystem WIN 11 Free-E-Mail bei Telekom Eingegange E-Mails werden auf dem Server von T-Online nicht gespeichert und auf meinem Thunderbird nicht im Ordner Posteingang sondern im Papierkorb vom Lokalen Ordner nicht im Posteingangs. Auf dem Handy werden Sie angezeigt und können gelesen und Bearbeoitet werden. Beim nächsten öffnen der E-Mail App werdenSie gelöscht.

Welche mögliche Ursachen gibt es dafür.