Hello, I try to create a TB account for a mail account *@outlook.fr. The account is not the current MS account of the windows session. Every thing is well set (joined screen capture). Following [[https://support.mozilla.org/fr/kb/microsoft-oauth-authentification-thunderbird|microsoft-oauth-authentification-thunderbird]] I should get , as described (french translation of the article): ''Selon la documentation Microsoft, les administrateurs et administratrices doivent visiter « https://login.microsoftonline.com/{tenant-id}/adminconsent?client_id=9e5f94bc-e8a4-4e73-b8be-63364c29d753 » et accorder les autorisations suivantes afin d’autoriser Mozilla Thunderbird : IMAP.AccessAsUser.All, POP.AccessAsUser.All, SMTP.Send et offline_access. '' But I get the "connect to an MS account" (see joined screen capture). If you validate (giving the password) then you have changed the current account of the Windows session which cannot anymore operate in normal conditions (particularly changes the current user of MS365 applications). Imagine that you have to activate several *@outlook.fr sessions, what could be the issue. In another way, as it is an IMAP account which is a "multi-user" function, several users are normally able to connect simultaneously which is opposed to MS account which cannot (must not - built for) be connected with several Windows sessions simultaneously. Consequently something goes wrong when you setup an outlook.fr mail account. It looks like the two connection : - connect MS365 account (linked to and id by *@outlook.fr) for contextual use of MS365 applications - connect to *@outlook.fr mail IMAP account to manage mails are somewhere confused. for now, I am unable to setup the configuration of mail for a team where several are using Thunderbird as mailer and others Outlook, while everybody of the team must have access to the e-mail of the team which is an outlook.fr mail account. Best regards, Trebly (trebly_auth)