Форум спільноти Thunderbird

After system complete reinstallation Ubuntu 24.04 it is not possible to send mails with SMTP Server. Receiving messages is possible!! Two fault Messages happen, I've two SMTP servers: 1. No connection to SMTP possible 2. Server timeout

And yes, I've checked nearly everything what's to find in the internet, reinstallation, change and check settings and passwords, together with the specialist from my provider. Also my provider is not able to find a mistake. As I've found out in the net, there are sometimes problems to connect to SMTP, but no solution found. Is there some security in the UBUNTU system, which blocks the SMTP connection or is this a bug from Thunderbird? Thanks in advance Andreas

bob.fannon

Feb 14, 2026, 13:01 CST

I have used Thunderbird for a number of years with Plusnet (using POP settings) in the UK. However, Plusnet has transferred their support to a company called Greenby who have made a hash of it and offer very poor support. So, I want to use Outlook as the mail server but I am unable to send any messages via Thunderbird to the Outlook server. I can however download messages with no problems. The error message I get is :- Sending of the message failed. Unable to authenticate to Outgoing server (SMTP) smtp.office365.com. Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'

My default Outgoing Sever settings are :- Server Name : smtp.office365.com Port: 587 User Name: bob.fannon@outlook.com Authentication method: OAuth2 Connection Security: STARTTLS

I have tried deleting the Thunderbird account and re-creating it but still got the same result. I also tried to use my old Icloud account ( having first setup my App Specific password) but got the same result.

I recently (unwisely) refreshed my WIndows 10. On restarting I had to reinstal Thunderbird. I thought I'd be able to recover all my old emails by importing the old profile from Windows.old, but I've had some problems: 1) I can't identify which profile was the most recent. 2) The info from each profile has remained on my Thunderbird, although I though it would be overwritten by the next profile I imported. 3) I've tried importing them one by one, but none of the old profiles is the one I was looking for, with all my sub folders. I need the old emails for work, invoicing and tax calculation purposes. I've now been sitting in front of my computer for a couple of days in a cold sweat, the desperation building quietly. Can anybody help?

We are facing issues with Thunderbird mail application.

Incoming emails are not being received in Thunderbird. Thunderbird is running very slowly and frequently becomes unresponsive. Sending and receiving emails is taking a long time. We have already restarted the application and system, but the issue still persists.

Kindly check the mail server settings and Thunderbird configuration from your end and advise on the necessary action to resolve this issue as soon as possible.

Your prompt support will be highly appreciated.

We're planning to switch from Outlook to Thunderbird, but we have a hard time in harmonizing font sizes on text and signature. One of the issues is that fonts can be set to textual values tiny, small, medium, etc. w/o knowing what it corresponds to in pt. But lets explain what we tried so far: - Under Settings/ General / Language&Fonts, we defined Calibri 12 as default, what we repeated under Advanced for 'Latin' & 'Other Writing Fonts' - Under Settings / Composition, we defined Calibri / Medium for the HTML Style - The HTML-signature is defined using the Calibri 12 font But when creating a new message w/ these settings, the result is terrible as you can see in the example: disregard the fonts' color, just look at the font sizes.

Is there any simple solution?

Every time I start Thunderbird it takes several minutes and sometimes doesn't start up. Once it does open up, emails do update new ones but if I go to account settings and select anything it hangs up. If I click on it, grays out and gets a message Thunderbird not responding. I have to open task manager to stop the program. Why aren't the emails on my email server get deleted/ moved updated when using Thunderbird? It seems like the only thing that happens only gets changed on the device I made changes to only. (computer, or phone or laptop)

all of a sudden, my deleted emails are not going into my Trash file. They are not spam. They are just emails I've already read.

Again, all of a sudden I have a Spam folder which I do not need or want. I want my Trash folder back and I want to be able delete my emails into that folder.

Right now, and this is new, when I delete an email it completely disappears.

I am in the midst of the long process of moving most (not all!) of my gmail from the gmail server to TBird, using filters as discussed in this thread.

I've started by first using filters on less important emails (ie so that no true disaster occurs if something goes horribly wrong). As I do so, I have questions!

For example, let's say I use a filter to: copy all the emails from @someone.org to a local folder then delete those emails (from the server)

What happens if one of those emails happens to be within a thread, including emails from people who don't match the filter (ie are not @someone.org). Have I broken the thread forever, ie, has something gone horribly wrong? If so, how do I prevent this behavior/have the entire thread move along with the targeted value? If not, I don't see how I can move email without breaking threads, which is a bit of a problem.

(Also - whoops, I see I should update, but the question remains.)

I've never had a problem before but suddenly I'm getting an error when I try to log into one of my accounts telling me "The STAT command did not succeed. Error getting message number and sizes. Mail server pop.gmail.com responded [AUTH] invalid credentials. Why is this happening now?

I have 4 other accounts on Thunderbird and this is the only one that has started giving me problems.

I am encountering a message of "The installation seems to be incomplete. Please check your hardware and disk setup and/or re-install." when trying to run Thunderbird.

This first occurred on a system that had been working for a while. An update may have been installed.

Here's what I've tried. -

Uninstall Thunderbird (along with Firefox and Mozilla Maintenance.) Checked for Program Files/Mozilla folder (all were removed). Run SFC / Scannow Run CHKDSK Installed pending Windows update. Restarted the System Renamed (essentially removed) Profiles folder Turned antivirus software off Downloaded and installed the latest version of Firefox, then Thunderbird. Launched Thunderbird. Still received the same error..

Any ideas on how to resolve the issue?

When i attempt to retrieve my email I get the following message at the top of my screen, "The certificate for POP3.pangia.biz expired of 8/13/26. How do I renew it? My email address is jahoagy@signalpeak.net. Thank you John Hoagland.

All my read emails are showing on the top bar of my thunderbird. I have to scroll left past multipee tabs to get to my inbox. This just started recently and at the same time email replies started showing up under the original. can I turn these features off.