We highly recommend using Microsoft Outlook when accessing e-mail. Outlook Web App (https://outlook.office365.com) is the preferred method. Outlook 365 and Outlook for Mac, which can be downloaded through the https://portal.office.com interface, are recommended if a desktop e-mail application is needed. For Linux users we recommend Mozilla Thunderbird be used. Since IMAP is disabled by default for all user mailboxes you will need to complete a HelpCenter ticket and request IMAP be enabled for your mailbox. We will look at the request and make the determination as to whether or not there is sufficient reason to enable IMAP for your mailbox. The request can be made at https://helpcenter.mines.edu/TDClient/1946/Portal/Requests/ServiceDet?ID=30257
If IMAP is enabled for your mailbox you can configure the mail client to use the following settings.
Incoming Server: outlook.office365.com
Port: 993
Encryption method: TLS
Authentication Method: OAuth2
Outgoing SMTP Server: smtp.office365.com
Port: 587
Encryption method: STARTTLS
Authentication Method: OAuth2
Thunderbird IMAP says "User is authenticated but not connected" message
Sometime at the end of December 2022 a change was made either in Thunderbird or Microsoft which requires you to disable IPv6 in Thunderbird.
In the main Thunderbird window click on the cog wheel in the bottom left hand corner OR click on File -> Settings. This will take you into the settings menu.
In the General section (this should be where you are already), scroll all the way down to the bottom and click CONFIG EDITOR
In the search bar at the top search for “network.dns.disableIPv6” without the quotes. By default this is set to False. Click on the TOGGLE icon (1st icon on the right hand side) so it toggles to TRUE. We want to disable IPv6. Once it is toggled to “true” then QUIT Thunderbird entirely, wait fifteen seconds, then launch Thunderbird again.