Thunderbird fails to authenticate Outlook.com IMAP account using OAuth2

I am trying to add a new Outlook.com email account to Mozilla Thunderbird on Windows, using IMAP with OAuth2 authentication. The account works correctly through Outlook.com webmail, but Thunderbird repeatedly fails to complete authentication. I have tried the following: 1. Configured the account using IMAP with OAuth2 authentication. 2. Checked the incoming and outgoing server settings. 3. Attempted to add the account several times. 4. Checked the POP and IMAP settings in Outlook.com webmail. 5. Tried using a separate Thunderbird profile to investigate the problem. Thunderbird does not successfully authenticate the account, preventing me from adding it. I already have existing email accounts in Thunderbird, including an ntlworld.com account and a Hotmail account configured using POP. My intention is to migrate my existing ntlworld.com emails and folders to the new Outlook.com account using IMAP. Could someone please advise why OAuth2 authentication is failing and what settings or troubleshooting steps are required to resolve this? I would particularly appreciate guidance that will not interfere with my existing Thunderbird accounts or stored emails.