Thunderbird コミュニティフォーラム

Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) smtp-mail.outlook.com failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again.

Seem to get this (or similar) error frequently. It's like the things I set randomly revert or change. Have sent images of settings. I certainly don't know what to do.

I am using Version 146.0, released December 9, 2025, on a Win 11 Pro, v. 25H2 pc. No problems until today. Messages won't download from two AT&T (ameritech.net) accounts. T-bird is not asking for mail key. No change after restarting T-bird; same result after rebooting pc. How do I restore email access? Thanks.

I use Thunderbird as my email client for my remote machine setup through Parallels Client desktop software for PC. After the recent update, every time I want to send an email, the compose window opens along with another browser window that displays my email account page home screen. Before only the email compose window used to open and after sending the email it would close. Now with the browser window that opens every time, i can't send another email until i close the browser. The attachment that i am including in my email also opens in the same browser window in a new tap and i have to manually close them.

How can i go back to just the email compose window to open and not the browser for every email?

Thanks, Yashar

Hi,

Longtime Thunderbird user. Was online last night, emailing (sending and receiving) perfectly fine. Got online this morning - no changes to my computer or Thunderbird, and suddenly am getting this message:

'Thunderbird could not connect to server inbound.att.net. The connection was refused."

I am able to read mail fine from AT&T Mail via webmail or the Yahoo Mail app. This is strictly an issue with Thunderbird and AT&T.

Any other AT&T users having an issue? Any helpful suggestions? If it matters, I have a bellsouth.net email address.

Thanks!

I have 4 emails in Thunderbird 2 are gmail addresses, they work fine. The other two are with my isp (knology/Wowway). The emails are on the Wowway website, but they don't download to Thunderbird. My server name is imap.mail.wowway.com, my port is port 143, connection security is STARTTLS, and normal password.

My last call to my ISP, they said they fixed the problem on their end, now it is Thunderbird's problem. I'm skeptical since they admitted they had a problem and they fixed it, but, can anyone help me? 10 days since it quit working!

Since T146 was auto-installed on 12/12/25 (I think), the Write window in which I compose new messages has ceased to close automatically, although the message is actually sent on time. I use Send Later (with a 5 minute delay). In troubleshoot mode, the window disappears - as it used to. Is there a problem with using Send Later on T146?

You seem to have addressed this topic well but not simple enough for complete non-techies like me who can really only do "Click X, then right hand click Y, then click Z" etc. Is there a noddy solution I could try? Thanks. Derek

After getting fed up with the Outlook app on windows. I decided to switch to TB. Now i can recieve my mails but can't send. I don't Use VPN and also checked if Windows Firewall is screwing things up. But those are allowed

Without the following. Unable to login to server (SMTP) smtp.office365.com with username *****@hotmail.com has failed (Translated from dutch)

These are my Settings incoming IMAP server: outlook.office365.com, 993, SSL/TLS, OAuth2 authentication, User Name = *****@hotmail.com outgoing SMTP server: smtp.office365.com, 587, STARTTLS, OAuth2 authentication, User Name = *****@hotmail.com

Optus (Australia) emails can't be sent or received by Thunderbird on my PC via my Optus wifi internet connection. I can use emails on my phone via mobile data with wifi turned off (different email client on the phone, though). Optus checked all the settings on my PC with me and they are all correct. They insist that it is a Thunderbird issue (doubtful, IMHO) and that I contact you. Is there an issue with Thunderbird connecting with Optus email? If so. is there any resolution to the issue? If not, can you confirm no problem from your end so I can get back to them (again!)

Recently my Thunderbird mail has been 'glitchy'.

Sometimes I receive audible alerts for emails, other times I don't.

Sometimes the number of new emails received is correct, other times it shows 4 new emails when, across all my accounts, the number is 2 (for example).

Are either or both of these known issues?

I also noticed when I was watching a live music stream on TikTok last week, I 'had' no emails for almost 2 hours. As soon as I left TikTok and closed my browser window emails 'arrived', one timestamped 45 minutes earlier. The settings for that account are set to check for emails every 5 minutes.

Could the Chinese be 'watching me' 😁 or is there another more innocent explanation?

I have been using Thunderbird for years for email accounts with Comcast (Xfinity), Yahoo, and gmail. Yesterday, I started having a problem with my Comcast accounts - when I sent a message, it went out, but I got an error message (attached) saying it couldn't save a copy to the Sent folder. Sending messages from my Yahoo account works fine. Sending messages from my gmail accounts, I get _two_ copies in the Sent folder (this is new).

I tried restarting my PC, and that didn't help. I tried Troubleshoot Mode, but that didn't help. I tried reinstalling Thunderbird, and that seemed to fix it, but then it started again. I tried compacting the folders, and that seemed to fix it, but then it started again.

I can connect to the Comast/Xfinity server fine, and things work. If I send an email from the server, a copy goes in the Sent file, and it then shows up in the Sent folder on my desktop. But emails that I send from the desktop don't show up in the Sent folder.

I am using a Dell XPS8950 with Windows 11.

Thank you for your help.

I was working on my email accounts when the messages in the inbox of one of my email accounts disappeared. The message count on the top left of my inbox display says 0.

How do I get them to show up again.  I am using Thunderbird on Mac OS 15.6.1

1) I need help in correcting the problem of why I am unable to send an email to someone and also 2) why all my emails this morning are going to ecurtis@neb-sandhills.net, which is the same consolidated website, and nothing coming into ecurtis@nebnet.net

When I click on an email, instead of just showing the email, it sets up a Reply screen showing From me and To Me. At the bottom there is an alert: "A unique identity matching the From address was not found. The message will be sent using the current From field and settings from identity......" (lists my email user name and address). Im not clicking Reply, I'm just double clicking the message to Read it.

Running Sequoia 15.7.2 on MacBook Air. It just started today. I have turned it off and on, no change.