Hello there Marilou.

If these Smtp setting were right , and filled in correctly in these normal fields. Try to see if antivirus software is running on that same pc machine and firewall configuration is available there to for to change settings so the direct connection cannot be disturbed or by maybe to implicated or to much settings in one time that could block these sending to your receivers. I had mine sendings to and receiver's did accept that mail yes that worked great on my device.I do use Antivirus to. What version do you use? What version of macbook do you use? Try to configure firewalls or Antivirus software to Thunderbird that it is allowed to use that port that is configured. As it or what is said in that pop up it could be a typo in your email name or login name.

Greetings Googlethunderbird

Thank you for your reply, and I am sorry I don't understand a lot of it. However: - I use a Macbook Air M2, v. Sequoia 15.6.1 (24G90) - the latest version - I use Thunderbird v. 140.5.0esr (aarch64) - the latest version - I don’t use an antivirus as it’s a Mac, but I use Malware Bytes for malware. - The firewall is turned off so all incoming connections to my macbook are allowed. - I have checked my account settings, they are correct for both Inbox (which I receive) and Outgoing (which I don't) - the fault only appeared about a week ago, before that it worked fine for both. All the best.

What are "Free-online mails"? Which is your email service provider and which are your outgoing server settings?

Hello there marilou

I did received that reply from you. The free online mails should be just the normal Thunderbird usage.(Mapenzi). What i did ment was that to many settings in the antivirus software for networks could create that no sending to option. The software malware bytes could disturb the Thunderbird software for the outgoing emails and even could also interfere some quarantined files.

You can try other antivirus software to defend your computer. Try to turn off the complete Malware bytes software for a while to look if that one is really that what the blocking the outgoing emails. Also for the look a like software s that is installed that also could be deleted. it could be that these unnecessary softwares do create or came together for slowing down the pc system and do create other symptoms. Malware bytes can scan using a third party antivirus could solve some . I think that other look a like or other programs can be the cause or that the scans of malware bytes do block that outgoing sending. Do you use the free software of malware bytes , can i ask?

Greetings google thunderbird.

the fault only appeared about a week ago, before that it worked fine for both.

There have been problems since Free-online changed to Greenby. Have a look at this recent discussion https://community.ee.co.uk/t5/Broadband-Landline/Email-client-problems-since-Free-online-changed-to-Greenby/td-p/1581657 I suppose you may find details about what has been changed in the outgoing server settings.

Hello there

For further information it is regular that wrong spelled passwords and outgoing server settings and smtp settings did create that pop up message.

Greetings googlethunderbird.

Hello there

Did you received notifications of plus-net ( free-online ) to transfer? Can i ask?

Greetings google thunderbird

Hello there

Thank you for using Thunderbird.

Greetings google Thunderbird.

Hello all, I'm very sorry I wasn't able to reply as I had a hospital appointment. And now I can't find a Reply box to the last posts, so I'll try and reply one by one, including your aliases. I hope this will do. Many apologies and thanks to all.

1. Mapenzi 11/17/25, 10:18 AM "What are "Free-online mails"? Which is your email service provider and which are your outgoing server settings? " When I mention Free-online emails, I mean emails sent from my Free-online address (provided by Plusnet). My email service provider is Thunderbird (all my emails are dealt via T'bird). My outgoing server settings are myname - relay.free-online.net.

2. Googlethunderbird. 11/17/25, 1:38 PM As I say, I don't use antivirus or firewall, and Malware bytes is the free version. And everything was working fine until a few days ago (ie with the same settings).

3. Mapenzi 11/17/25, 2:02 PM I have been in touch with both Plusnet and Greenby because I kept receiving emails telling me I had migrated, but when I queried about Free-online specifically I have been told it has not yet migrated. It's really not clear but will have a look at your link.

4. Googlethunderbird. 11/17/25, 2:25 PM I have checked the spelling, several times, and it has not changed since the initial set up.

5. Googlethunderbird. 11/17/25, 2:45 PM If you mean the 'migration', yes I have, see Point 3 above. I was told to do nothing until specifically instructed to do so. I can copy and past the conversations if useful.