Setting for outlook office 365 email in Thunderbird

POP settings:

Server name: outlook.office365.com
Port: 995
Connection Security: SSL/TLS
User Name: full email address
Authentication Method: OAuth2

IMAP settings:

Server name: outlook.office365.com
Port: 993
Connection Security: SSL/TLS
User Name: full email address
Authentication Method: OAuth2

Office 365 SMTP settings:

Description: full email address
Server name: smtp.office365.com
Port: 587
Connection Security: STARTTLS
User Name: full email address
Authentication Method: OAuth2

Note: For accessing the SMTP need to enable the Authenticated SMTP in admin console.

1. Open the Microsoft 365 admin center and go to Users > Active users.

2. Select the user, and in the flyout that appears, select Mail.

3. In the Email apps section, select Manage email apps.

4. Verify the Authenticated SMTP setting: unchecked = disabled, checked = enabled.

5. When you're finished, select Save changes.