Thunderbird Community Forum

The certificate for pop.3marysvilleprint.com is not vailid for that server. Someone could be trying to impersonate the server and you should not continue

I want to copy my windows Thunderbird profile to Linux but my Profile Directory will not open when I press open directory. I downloaded Thunderbird from the Zorin app store, and it may be a flatpak or something – it won’t tell me now because I have already installed it – but I believe that could be a reason for the directory not opening. Is there a non-PC-literate way of finding out and fixing this?

Hello,

I followed the steps to use the vCard option as a Email Signature.

When creating a new email the vCard Signature is not appearing.

Please Advise,

Rodney

I have had Thunderbird from the time I acquired my Mac computer. This week it started to do something new. After a restart I opened Thunderbird. A box came up that says across the top System Integration. The cursor balloons, and hasn't stopped for the time I powered the computer, as least fifteen minutes. You know how the program icons are in a dock across the bottom. With other browsers open, hitting the Thunderbird icon doesn't bring its window into the forefront. This needs either a reset, or possibly a backup first. Is there a quicker way to fix this? Thanks in advance. I am not using a VPN; but I also have Thunderbird on my Windows 11. You might have seen a more recent thread on that installation. I included a screenshot. It was easier here to do that than on the Windows 11. On the Mac, I just had to use Activity Monitor to close out of Thunderbird in order to get its version.

After the most recent update to Thunderbird, I can no longer copy attached files on incoming emails to either my Quickbooks program or a folder on the hard drive by dragging over. Now must copy manually to drive. Can this be corrected?

I am assisting an elderly user with a personal @hotmail.com account that receives email successfully in Thunderbird but cannot send. I have confirmed they can send and receive emails from their online outlook.com portal. The user's computer setup is as follows:

• Windows 11 (with latest updates).
• Thunderbird 153.0.2 (64-bit).
• A personal @hotmail.com account with the following server configurations:

  -> Incoming IMAP: outlook.office365.com, port 993, SSL/TLS, OAuth2, and
  -> Outgoing SMTP: smtp-mail.outlook.com, port 587, STARTTLS, OAuth2.

Thunderbird successfully authenticates to Microsoft using OAuth2 for incoming email. However, when Thunderbird attempts outgoing email authentication, Microsoft's SMTP server rejects the authentication. The Error Console in Thunderbird records this message: "535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox."

-> Refer to attached image: "Thunderbird Error Console_20260811.jpg". -> I am able to provide a short screen recording demonstrating the failure if needed.

To try and resolve the above, I completed the following actions:

1. Confirmed Thunderbird is current (153.0.2).
2. Confirmed SMTP is configured for OAuth2 rather than Normal Password.
3. Confirmed port 587 and STARTTLS.
4. Re-authorised the Microsoft account/OAuth connection.
5. Confirmed IMAP OAuth2 works.
6. Confirmed Outlook.com webmail can send successfully.
7. Reviewed Mozilla's current “Microsoft OAuth Authentication and Thunderbird in 2026” guidance, including the section covering cases where IMAP/POP works but SMTP does not.
8. Captured the SMTP failure in Thunderbird's Error Console.

However nothing worked, so I raised the matter with Microsoft support and eventually had the matter referred to their Tier 2 team. The Microsoft case number is: 7107041963.

Microsoft Support confirmed that for a personal Outlook.com/Hotmail account there is no user-accessible mailbox-level SMTP AUTH setting, and advised that SMTP is enabled by default for supported clients. However, because sending from Outlook.com webmail works, Microsoft Tier 2 declined to investigate the SMTP server response further and directed me to Thunderbird support.

I am able to provide a copy of the chat transcript if needed.

In any event, the TLDR version IMAP works using OAuth2, but SMTP using OAuth2 fails because Microsoft's SMTP server reports SmtpClientAuthentication is disabled for the Mailbox. Microsoft Tier 2 has referred the issue to Thunderbird support.

Questions:

1. Is this a known current issue affecting personal Outlook.com/Hotmail accounts using Thunderbird?
2. Is 535 5.7.139 SmtpClientAuthentication is disabled for the Mailbox known to occur with Thunderbird OAuth2 even though IMAP OAuth2 succeeds?
3. Is there a current Thunderbird-side workaround or alternative SMTP server/configuration recommended for personal Hotmail accounts?
4. Would changing the SMTP server from smtp-mail.outlook.com to smtp.office365.com be appropriate for a personal Hotmail account in Thunderbird 153, or should the current Microsoft-documented server be retained?

-> I note there appears to be conflicting advice on this point in previous support threads.

1. Given that IMAP OAuth2 authentication succeeds for the same Microsoft account, does this indicate that Thunderbird's Microsoft OAuth authorisation itself is functioning correctly, or could SMTP require a separate permission/token that may be failing?
2. Are there any additional Thunderbird logs or diagnostics I can provide that would help resolve this matter?

Disclosure: I used ChatGPT to help organise my troubleshooting notes and technical details for this post. The troubleshooting, observations and diagnostic information described above are from my own work on the affected PC.

Im looking for help to set up my Hotmail account. I have 4 emails. They all worked perfectly for a long time. All of a sudden, everything just stopped. I have tried everything and the configuration seems to be correct. Ive tried every fix i could find. It just no longer makes sense to me. Does it just not work with Thunderbird? The specific message is "User is authenticated but not connected". Also when i tried to send an email, i get "Login to server smtp-mail.outlook.com with username **********@hotmail.com failed."

Sending of the message failed. An error occurred while sending mail. The mail server responded: <support+idMM51X2-RWD3K@dealerbuilt.zendesk.com>: Relay access denied. Please check the message recipient "support+idMM51X2-RWD3K@dealerbuilt.zendesk.com" and try again.

the above is the error code. I have triple checked emails, even tried sending a message to my personal email as a test and nothing.

Just updated to the latest version 153. No drag and drop ... message shown is 'Unspecified Error'. I made no changes when updating to this latest release. Appreciate some guidence. Thanks

My Thunderbird install updated from 140.13.0esr to 153.0.2esr yesterday and now I can no longer drag and drop any attachment from an email to any folder on my computer. I simply get an error message window with a title of "Error Moving File or Folder" with "Unspecified error" text. See image attachment.

I've tried a variety of folders, including Downloads, Documents, Pictures and other folders on local and external storage devices.

I can save the attachments using the Save All button, or by right-clicking a file and choosing Save As, but not by dragging and dropping as I have done so for years.

I have checked if Thunderbird is running in admin mode, which it is not, but have tested it both ways with the same problem occurring. I have also run Thunderbird in Troubleshoot mode, and the same thing occurs. I tried clearing the startup cache from the troubleshooting page with no change. Restarting the PC did not resolve the issue, and disabling my anti-virus(Avast) also did not make a difference to the issue.

All was well until about six months ago. When I try to connect to my provider TB won't connect. BUT. At other times it will connect then every few minutes will try to connect again - then again .... I get this message "Connection to the server mail.comcast.net timed out". Then I get this message each time it fails "Login to server mail.comcast.net with username 170834000 failed". It keeps asking me to input my password even though everything is working appropriately. Then at other times it says it doesn't connect but it has connected and it still continues to ask me for a password.

I have uninstalled TB and reinstalled it thinking that would fix it - it didn't. I have changed my password - again to no avail. I let TB choose where to put things and configure each item appropriately. I don't try to get in the way of what works.

Comcast is apparently getting out of the email business and asking everyone to move over to their chosen substitute (Yahoo.mail) and I have not chosen to migrate at this point. Maybe that's the problem. This is the message I get each time I log into Comcast.net:

"A better email experience is now available for you

You're invited to upgrade your email account to Yahoo Mail, so you can enjoy a more user-friendly experience. Your email address, messages, folders, and contacts will not change.

With Yahoo Mail, you'll enjoy enhanced security, a built-in calendar that's easy to use, AI-powered inbox organization, and a top-rated mobile app for easy access on the go."

I am not aware of any changes in the settings from before when it was working well and now when it seems to be erratic.

I am not terribly computer savvy, but I'm usually able to trouble shoot and fix the issues that confront me. This time I'm out of my league! I need help.

Thank you for helping me.

Until recently, Folder Panes were visible at all times, but after the most recent update, they only appear when I am on a folder and are not visible when I am on a message. I have activated Views/Folders/Folder Pane Header, but that does not solve the problem.

Shortly after my most recent update, my Sent folder became corrupted. Rather than containing recently sent messages, it contained older messages from another folder, and when I send a new message now, it is not added to the Sent folder. When I tried to send a message, I received an error notification indicating that the message could not be archived because the folder did not have enough memory. I deleted everything from the Sent folder and then compressed it, but that did not solve the issue. I then closed Thunderbird, manually deleted the Sent folder from Mail/Local Folders; the Sent file was regenerated when I started the program again but with the same issue. I then backed up my profile, removed Thunderbird and reinstalled it, and then copied my profile over without the Sent folder. But when I opened the program, the issue still persisted.

The folder properties for the Sent folder indicates:

Name: Sent Location: mailbox://nobody@Local Folders/Out -- 148 November-Dec 2022

The location is obviously incorrect as it does not point to the Sent folder, but rather to another folder I use to store older message. I see no way to change the location, and the Repair Folder option does not solve the issue.

I would be very grateful for any suggestions.

No new messages have downloaded since July 31. I am very disappointed as there are several things I need to access and no way of getting support. I feel like I keep trying to email and ask questions but by using my Gmail and not my current WB for me.com email it is confused and I have been looking on Mozilla support for similar questions, but seem very overwhelmed and have tried a few of them and restarted it several times but not resolving the issue. Can someone please help and if possible give me a call <redacted>. I’m not sure how I’ll get the answer if any from this site but hopeful that it is sooner than later because I really need to get it done today.

For a few days I'm having trouble with Asana mails (notification mails informing me about replies, comments, etc).

Clicking on the mail to view it freezes Thunderbird for a good 5 seconds while one CPU core spins at 100%. This only happens with Asana mails (or at least I haven't found any other problematic senders).

I guess it's a problem with validation or parsing of the mail's HTML content. But I don't know how to debug this.

I can't pinpoint exactly when it started happening, but it was around the time I've switched to the [new snap release track](https://support.mozilla.org/en-US/kb/channel-choices-thunderbird-snap-and-flatpak#w_snap-channel-changes-in-2026). But since this happens with Snap and Flatpak I think the culprit may be the 153.0 update.

Things I've tried:

• Clearing cache and msf files.
• Troubleshooting mode with add-ons disabled.
• Reinstallation. Creating new profile + importing old data.
• Switching from Snap to Flatpak
• Switching Message Body display to Plan Text or Simple HTML.
• Disabling HW acceleration.
• Checking console for suspicious output.

Anything I can do to create handle the problem or collect information for a proper bug report?

I prefer to have the Contact Name only display in the TO: field of composed or outgoing emails. I already know their address is correct in my Address Book, why do I need to see it? Presently, the TO: field shows "Name <email address>", as shown in the first uploaded image.

I am a new user to Thunderbird and I have reviwed, and believe, set all the Settings correctly that I could find on the subject (see second uploaded image), but the results do not change.

What am I missing?

Thanks Matt T