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Not sure which "topic" best describes my question, so . . . .

OS: Windows 11 Thunderbird 140.1.0esr

I have been using T-bird for several years, and have made to changes to configuration in recent memory. Beginning today, when I try to send an email through my Comcast account, it fails with the following message:

“An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-h2p-555031.sys.comcast.net resomta-h2p-555031.sys.comcast.net EXMTP server not available.”

The outgoing SMTP server is configured as follows: Outgoing server: smtp.comcast.net Port: 465 Security: SSL/TLS

For comparison, sending email from my Android phone, using the Gmail client with the same server specs, also fails, thought it gives no information.

For more comparison, I configured Outlook to test with it, and it was able to send successfully. I noticed in setting it up that it used the same server name, but with port 587. Armed with that information, I changed the port setting in T-bird to 587. With that change, the send still failed but with a different error:

Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.comcast.net was lost in the middle of the transaction. Try again.

Any help is appreciated.

Hello all,

Thank you for Thunderbird mobile!

I get a message not sent error when doing the following on Android smartphone: - click an email address link - create email opens - send completed email

Expected result: Email goes to outbox and is removed after sending

Actual result: - email stays in outbox and error cannot send is displayed - when moving email to Entwürfe and send again the sending succeeds, but email is present twice in sent folder

Please have a look!

Best regards Gerrit

A couple of days ago, there was an update to Thunderbird and since then, my emails have been coming in to wrong folders. None of the emails coming in to the inbox are staying there. They are instead going into a subfolder of my inbox set up to filter online orders coming in to my business. When I try to move them back to the inbox they disappear nowhere to be found.

I don't know what to do. Who is supposed to help in situations like this? My business is being affected by losing emails into cyberspace and all my message filters going wacky.

I have setup Thunderbird to check for e-mail each 30 minutes. But I never get any notifications of any new mails :-( And mails are only downloaded when I start the app and swipe down. Folders are setup to sync (but "push" is not enabled). Power settings are set to "Optimized" (works for all other apps that check for things).

I've used TB successfully for many years to access several Yahoo and Googlemail accounts. Windows 10. Recently the Yahoo accounts don't work so I've tried several times deleting and reloading them. This may be a red herring but the trouble seemd to start when I installed TB on a new Windows 11 laptop and failed to load the Yahoo accounts. I've tried following both Mozilla and Yahoo help articles but ultimately success is partial at best (i.e. incoming works, outgoing fails) This is the sequence I have followed

251128 tried this: Deleted all yahoo accounts in Thunderbird

Edited outgoing yahoo server to

 smtp.mail.yahoo.com
 Port 465
 SSL/TLS
 Authentication method OAuth2
 User name johngherrett@yahoo.com

Added yahoo account johngherrett@yahoo.com name and email address

opens yahoo! login sequence enter email and yahoo account password - FAILS

logged out of Yahoo mail open elsewhere

Accept 'Configuration found in Mozilla ISPDB'

opens yahoo! login sequence enter email and yahoo account password - FAILS

Account Hub window 'Choose your email type' pick 'Edit configuration'

Changed Incoming server settings to: POP3 pop.mail.yahoo.com Port 993 SSL/TLS Auth method OAuth2 username = email address

Test

'Outgoing server settings' 'The following settings were found by probing the given server' SMTP smtp.mail.yahoo.com Port 465 SSL/TLS OAuth2

Continue

Authentication error 'Unable to log in at server. Probably wrong configuration, username or password.'

followed guidance from Mozilla article: https://support.mozilla.org/en-US/kb/thunderbird-and-yahoo Exit Thunderbird Wait a few moments for background process to complete Start Thunderbird

counted to 10+

restarted Thunderbird Yahoo account is not there Googlemail account is there - OK

'Set up another account' - email started again Name & email

opens yahoo! login sequence enter email and yahoo account password - FAILS: 'Something went wrong' - not helpful 'Go to help' in Yahoo dialog opens another page in kanji(?) close this

back in TB Account Hub window 'Choose your email type' pick 'Edit configuration'

Changed Incoming server settings to: POP3 pop.mail.yahoo.com Port 993 SSL/TLS Auth method Normal password [changed] username = email address

Test

'Outgoing server settings' 'The following settings were found by probing the given server' SMTP smtp.mail.yahoo.com Port 465 SSL/TLS Auth method Normal password [changed]

Continue

'Creating account'

'Authentication error' as before

Go to https://help.yahoo.com/kb/sln27791.html Login to yahoo account 'Ways to securely access Yahoo Mail'

Use an app password ************

Signed out of a 'current sessions' even if not recognised. (Except 'current device' which is the login just past.

External connections-> Create app password App name : Thunderbird Generate

Copied to clipboard ********************

Returned to TB

entered password 'Continue' Spinning icon and re-opens yahoo login dialog entered normal password 'Something went wrong'

entered app password 'Something went wrong'

Despite this, after closing the yahoo dialog, TB says 'Account created successfully'!!!!

Inbox appears

Note:server settings now set somehow to IMAP / normal password

Testing outgoing: Message fails, Yahoo dialog login fails Edit outgoing server which remains OAuth2 Changed to normal password

Tried app password - failed Tried normal Yahoo password - failed

Hey everyone,

I’ve noticed that on Thunderbird for Android, some of my email accounts get new messages with a delay of up to 15 minutes. I’d really like to get them instantly (or at least much faster).

A few details: - The email server is my university’s, so it might not have the latest sync features. - I set the folder poll frequency to 15 minutes, and emails do come through fine that way — just too slow. - I also set “refresh IDLE connection” to every 2 minutes. - Running version 13.0 of Thunderbird on Android.

Is there any way to make Thunderbird fetch or push emails instantly? Or is this delay just how it works if the mail server doesn’t fully support push/IDLE?

Thanks for any tips or ideas!

This was working ok until today. Now, only ONE of my mail accounts is sending mail to the "All Mail" folder as "Unread" and NOTHING is going to my Inbox. Anyone have an idea what could be causing this?

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

Following a switch off and restart triggered I think by a Windows update, Thunderbird is not displaying any messages in my Inbox, though it is showing the number of messages in the Inbox title bar. 'Drafts' and 'Sent' all display correctly, but the 'Inbox' is blank with a grey icon of an envelope and the statement: "No message found". I am an IT novice. I looked on the 'help' pages. I have checked that no filters are set. I have right-clicked on the 'Inbox' title to display the menu with 'properties' at the bottom. I have clicked on that to bring up the dialog box with the "Repair" icon. It shows 'Inbox' in the 'Name' box but I note that the 'Location' box is blank. Presumably it should not be. Presumably it should show either the location of locally stored messages on my hard drive, or the location of the messages on the email server. I am not sure which. I have found the directory on my hard drive where I believe the messages are stored locally. The size of the file suggests to me that they are all there. The periodic 'Checking for new messages' is happening, but nothing is displaying, though a check via webmail shows that new messages are arriving on the server. What should I do to get my Inbox to display correctly? With many thanks, Iain

Thunderbird (140.2.1esr) suddenly stopped downloading emails on 8th Sept 2025, although new emails are still accessible on my email server's webmail, suggesting the problem is with Thunderbird not accessing the server. Sending messages in Thunderbird is unaffected. Have tried every solution I can find online, but problem still persists. When I click 'Get messages' , at the bottom it says 'Host contacted, sending login information', then 'Checking inbox for new messages', then 'No messages to download'.

I believe I found a bug. When drafting an email and switching away from Thunderbird the draft email gets sent but still remains in the drafts folder.

I created two emails today and had to switch away multiple times to get some information to paste into the emails. Thunderbird evidently sent out the draft in its current format whenever I switched away from the app.

I must be doing something wrong. I am new to thunderbird, migrated from Eudora since I can't send mail with Eudora anymore.

I tried to configure Thunderbird as much as possible like Eudora, but ... it doesn't receive nor send mail. On the surface it looks fine, it seems thunderbird logs into the server, it seems it sends mail and checks for new mail, only I don't receive anything, nor send anything even though it looks it does. So what am I doing (or is going) wrong? (I can still receive mail with Eudora and today I checked and received 54 mails, none with Thunderbird)

I've been "sending" e-mail from my Android phone for six weeks now. It looks like it's going out, but it never gets outside the domain.

I found the suggestion that I check my SMTP settings, but I used a wizard within TB for Mac so I cannot find the SMTP settings on the phone.

The wizard wasn't very wizard: I don't have the contacts stored within TB or the mail from my computer or anything. All I can do is receive e-mail.

I really need to get this working. My computer has died, and everything is going via the phone, and I only use e-mail for communication, not voice or text. (Long story, please don't argue with me about that.)

I just updated Android again yesterday, and TB should be upgrading automatically, if I have this thing set right.

Update: I have found the SMTP settings. They look correct.

My sister's e-mail is working, so the problem is definitely with my settings somehow.

Does anyone have any ideas? I really want to stick with TB.

Update 2: I found the debugging settings and turned on extra logging, but I can't find the logs themselves. Could someone point me to them?

I also tried the TB beta because it says explicitly that it does POP3, but that didn't seem to help either.

Now that I can edit my question, how do I delete the answers that are actually just updates?

Update 4: A different app works. I'd rather use TB if it can be arranged, though. . . .

Any help would be appreciated!

Thank you!

Running Thunderbird with three accounts on my desktop PC - two 'btinternet.com' accounts and one 'gmail.com' account. Inboxes have no more than 20 emails in them, as I delete unwanted ones and transfer others to various sub-folders ( In excess of 40 No.). Today I suddenly found that incoming emails on both bt accounts were not showing the subject or sender and the content is displayed in plain text (txt) format - no problem with the gmail account.

I have compacted and repaired the inbox folders but no difference. If I send a message from either of the bt accounts to the other the problem occurs, but if I send a message from either of the bt accounts to my gmail account, it goes through fine. I can receive bt emails fine on my laptop. I assume this is a thunderbird problem on my PC but not sure where to start - would be really grateful for any guidance.

Several days ago we inadvertently deleted batches of emails from our two Thunderbird Gmail accounts on our PC and Apple devices. The lost emails were duly recovered but only after having to change my Google password. However one of our Thunderbird Gmail account will not download any new messages coming in. Ultimately we deleted that account from Thunderbird, intending to reinstall it. We deleted the account by pressing the Red button in account settings. We confirmed that messages are received to Gmail's Web page Inbox Now when I attempt to reinstall the account and press Add Account, I get the UNABLE TO LOG IN AT SERVER MESSAGE shown below. The "Your Full Name" I am putting in is the name on the Google account deleted from Thunderbird, and the password I have tried is my new Google password. I have tried the process of not adding in the password until requested to do so but this did not work either. Any suggestions please?

As of today I can receive emails but I am not able to forward or to reply to emails and I can't create a new email. When I click on + New Message nothing happens, the write window doesn't open. I can't get the send new email window. All the above options, simply no longer open a new corresponding window.