They are saying that, in the language of TB, 'normal password' authentication won't be supported. But OAuth2 authentication will be supported, as it has been, in both TB and MS accounts, for well over a year. See this topic for the relevant settings, if you don't already have them:

https://support.mozilla.org/en-US/questions/1417298#answer-1588949

Thank you. I will see what happens from 16th September.

If I need to change the settings to those shown in the screenshot, where do I find / how do I display this screen to make the changes?

Tools/Account Settings, Server Settings, and Account Settings, Outgoing Server (SMTP).

Thank you very much 🙂

sfhowes I need further help please.

I made the changes to my email accounts and they stopped working.

After changing from Port 993 to Port 587 and changing from SSL/TLS to STARTTLS the Default Port displayed to the right of 587 I had selected immediately changed to show 143.

I presume this is the reason why my email accounts stopped working.

I do not know how to create Port 587 with the Default as 587

First image shows Server Settings displayed after making the 3 changes.

Second image shows current settings for my Gmail accounts - Note that 0Auth2 was set automatically.

Third image shows current settings for my Microsoft accounts - set automatically.

Fourth image shows Connected after I sent an email to another of my accounts - it went on for a long time (before Timed Out message displayed).

Fifth image shows a message - it was displayed one time only.

Sixth image shows Timed Out message - it was displayed repeatedly.

These are the correct Hotmail settings: incoming outlook.office365.com, 993 (IMAP) or 995 (POP), SSL/TLS, OAuth2, email address; outgoing smtp.office365.com, 587, STARTTLS, OAuth2, email address.

Timeouts are a separate issue, often caused by antivirus interference. If your AV is not the built-in Windows Security/Defender, remove it, then try connecting with TB.

Thank you again

I don't know how to expand the Server Settings to check / change both incoming AND outgoing.

I can only see the Fields as per the first image I posted.

If you can give me further guidance and I am able to input the correct settings for both, I will see if the Timeout issue arises again. It has never been an issue with the current settings.

I could disable Bitdefender Total Security to experiment, but would never remove it from my PC's.

Account Settings, Server Settings to set the incoming, Account Settings, Outgoing Server (SMTP) at the bottom of the left pane for the outgoing.

Sorry to be so 'thick' but I cannot see anything at the bottom left of the Server Settings screen to set outgoing.

Local directory is the last thing at the bottom of that screen.

Also for the incoming, is it ok for the Default Port to show 143 after changing Port to 587 and SSL/TLS to STARTTLS

See attached screenshot. incoming port of 143 and STARTTLS should be okay. if not, try 993 (for IMAP) or (995 for POP) with SSL/TLS

Hello David

Thank you for your response.

Ah, 'the penny has dropped'! I now realise that I was confusing the incoming and outgoing settings.

All I need to change on incoming settings is the Authentication method - from Normal password to OAuth2 - on Microsoft email accounts. The Gmail default setting is OAuth2.

If I need to make changes to outgoing settings I still need help to 'find' the screen displaying these.

I cannot find the image of your screenshot in Thunderbird Settings - Account Settings - Server Settings

In his earlier response sfhowe directed me to the bottom of the left pane in Server Settings but I do not see them there.

The left side lists all accounts. Directly below that are Local folders and below that is 'Outgoing Servers (SMTP) . That left side is in view for 'account settings' whether you click 'server settings' or others. It may not be at the bottom, but will be below the accounts.

Thank you very much David - and my thanks again to sfhowes

I found Outgoing Servers (SMTP) and all the settings shown match those sfhowes listed.

I will now change incoming server Authentication settings on all my Microsoft email accounts to OAuth2.

I hope that when 16th September arrives I won't encounter any problems in receiving and sending emails from my accounts.