I checked the installed Programs on My Windows 8.1 laptop, and saw that two x86 versions of Thunderbird are installed - 115.10 on 05/07/2024 and 115.118.0 on 30/06/2025
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I checked the installed Programs on My Windows 8.1 laptop, and saw that two x86 versions of Thunderbird are installed - 115.10 on 05/07/2024 and 115.118.0 on 30/06/2025
Should I remove version 115.10?
Could two installed versions be causing the following to happen?
I have set incoming server settings correctly for each email account - outlook.office365.com SSL/TLS, OAuth2 and the outgoing server settings are correct - smtp.office365.com Port 587, STARTTLS, OAuth2
Microsoft is repeatedly requiring me to enter passwords for email accounts.
This message often displays: Login to server SMTP.Office365.com with username x failed.
When I click 'Send' I often receive: Sending of the message failed. Unable to authenticate to outgoing server SMTP-mail.outlook.com
and
Authentication failure when connecting to server Outlook.Office365.com
Advice on anything else I should check / change will be greatly appreciated. Thank you!