Thunderbird Community Forum

Purchased new laptop. Used export tool in Thunderbird to external HD. Traded in old laptop. Installed Thunderbird & attempted to import my email profile. Import tool requires zip file, but the only file on my external HD is a .default file. I'm getting new email but none of my old emails. Consulted Best Buy Geek & he determined the import tool didn't work properly because the export was missing required files. We further determined the export backup must not have worked properly.

I can receive, but not send, emails using Thunderbird on my PC. I believe this problem began when Thunderbird was updated on 1/13/26. I have no problems sending email on my tablet.

My service provide does not support TLS 1.2, so I tried changing security.tls.version.min to 1. This did not help.

The attached shows the error message and my SMTP settings (1st image) and my service provider's email server settings. I tried changing the SMTP port to 587, but this resulted in a time out error.

Any help is appreciated, Norm

I´m well trained employee in user support and server administration for more than 30 years now. So long for my skills... I´m the administrator of a Microsoft 365 tenant. A user asked some days age, as he can´t login into his M365E3 account using Thunderbird. I tried this scenario in my private Thunderbird profile and indeed I get an weird dialog box. I can insert my password above the first line, input above the second line is readable in clear text, the checkboxes are selectable, but no button for continue. I have examined https://support.mozilla.org/de/kb/microsoft-oauth-authentifizierung-th..., but have no success. Whats going wrong here and how can I help for debugging? Environment: TB 147.0, disabled extensions, Windows 11 pro german 01-2026 patch M365 account with MFA, (Microsoft authenticator app as primary option)

All of a sudden when I go to check email it wants a password and I didn't know I had one. When I put one in it won't take it. How do I get in to check email. I'd have you email the answer but I won't get it because I can't open it.

Hello, My SMTP server uses Let's Encrypt certificate. The website with the same domain has no certificate. Thunderbird refuses to connect to my SMTP server. Test connection to the server (STARTTLS) in account settings sais "The secure connection to the server failed" (or similar. I see bg localization). Another server with Let's Encrypt certificate. Test pases. Clicking View certificate shows webserver cert (from DigiCert Inc).

I can't send emails! :)

Regards! Valentin

Have been trying to set up some pop3 yahoo mail accounts on a new computer. I have used automatic configuration. I have used manual configuration using the data from my old computer. I have checked the configuration settings on both Yahoo and Thunderbird sites. In all instances Thunderbird verifies the account is valid, but the next window asks for my yahoo username and password. I cannot get passed this stage. I have tried entering my yahoo password and I have also tried the app generated password from Yahoo, all I get is a Yahoo "something went wrong" message. Interestingly I did manage to get one of the accounts to work yesterday, but I must have tried no end of different permutations and I have no idea which one eventually worked.

Hi all,

After thoroughly searching this database, I could not locate an answer to the issue I am facing, although there seem to have been several similar cases.

My former university has recently decided to delete alumni email accounts, so I am using Thunderbird for email transferring from university to GMail (added both accounts to Thunderbird and then began copying emails and folders). Transfer is slow, depending on the server capabilities etc., but I am going folder by folder and so far it has been fine. I began the transfers a week ago.

Last night I noticed my Thunderbird inbox for my school is not showing anymore. The profile folder is only showing one file (.msf) for Inbox, instead of what should be, in my understanding, two files.

Thunderbird is still communicating well with the university email server because I made a folder rearrangement on the university webmail service (outlook.com) and it showed on Thunderbird. In addition, all my Inbox emails appear fine on the university webmail service (outlook.com).

Any ideas? This is obviously important and urgent.

Thank you in advance.

My pc calendar display is blank. I can create new event in Thunderbird on my pc and it is immediately appears in my google calendar on my mobile phone, but does not appear on my Windows 11 PC.

I have been using Thunderbird on my laptop for a few years. It stopped retrieving my emails and I have not been able to get any emails on Thunderbird since June 24, 2025. I have tried changing the pop3 & smtp settings to those currently recommended by at&t but it hasn't worked. Please help!

Today is 01.16.2026 Hi Volunteers, thank you for the service you are providing Thunderbird users.

I didn't see a topic called Security, so I chose Settings.

For Thunderbird version 146, what specific version of LDAP is being used?

Regarding which LDAP version is the most up to date, I found this: https://pkg.go.dev/github.com/go-ldap/ldap/v3@v3.4.12

My concern is about LDAP's security. I believe it is reasonable to think that the latest available version of LDAP would have the latest and most up to date security patches applied.

I would like to feel secure knowing I have the protection of the newest version of LDAP which affords the best security protection available for Thunderbird laptop version 146.

However I have been unsuccessful in determining if Thunderbird 146 is using this LDAP latest version. Could you help me learn if Thunderbird 146 is utilizing the latest version of LDAP that is available? Thanks in advance.

Yes I know I am a bit verbose.

Hi, The question is in the title. I have imported my Outlook data in this 32-bits version (updated to 140.7) . I would like to keep them in a 64-bits version (147). I didn't find the solution. Thank you for helping me. Michael.

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.

I have two email accounts, one is hotmail.com, the other is on outlook.com

The SMTP for the outlook account works fine, but Thunderbird puts that same smtp details into the Hotmail account smtp. That also puts into the Hotmail username, the outlooks email address.

If I try to send an email using the Hotmail account, I get a message saying 'Hotmail can not send using xx@outlook.com

If I use the settings to make the username xxx@hotmail.com, it puts that into the smtp of the outlook.com address then that will not send giving the same fault. This has only started this last couple of days, nothing changed in the settings.

This only occurs on my Desktop. On my laptop with same settings it works fine.

Thunderbird is showing up to date?

Help Gerry

How do I restore selected emails or folders from a backup made with Export? I only want to bring in 30 or so (which were accidentally deleted). I'm using a Windows 11 PC.

I'm nervous about reloading the backup because it was some time ago (and I *really* don't want it to download new emails).

Just updated from Ubuntu 20 to 24. Seems Thunderbird has not been auto-updating. I have three email accounts, each with multiple folders and sub-folders. I have three windows open, one for each account because they are for three purposes. Before the change each full height window could accommodate all the folders for its account (plus the un-expanded two lines for the other accounts). Now the folder lines are further apart and they don't fit so I can't tell when a new message arrives in one of the other accounts. Is there a setting for the spacing of the folder listing, and if so, what is it? Similarly I can not see so many messages listed in the classic layout without enlarging that pane and reducing the space for the messages. The spacing is larger than it used to be. Does it have a setting?

Thanks, David