Managing personal Outlook.com account settings, security, and privacy
With regard to Thunderbird, I posted this reply copied here to another user in
a different thread and believe it could be useful to add this here as well. These
2 specific steps are needed to be done to make Thunderbird compliant with
requirements for sync the Thunderbird email client app with Outlook. Having
done this recently I can confirm this works. Likewise the description of how to
export the eml files from WLM or Outlook that I posted in the message above
is recently confirmed by me to work.
So for anyone that is making the change to Thunderbird,
Please let another T-bird user help you out here, just because I can.
This will require 2 steps to get you compliant using T-bird to access an outlook account,
and it is a combination of server settings in T-bird as STEP [1] along with STEP [2] permissions
settings for Outlook that must be accessed through the web portal for Outlook opened
in a web browser and clicking the gear icon there to select your Mail tab and grant
permission for Thunderbird to access your Outlook account.
STEP [1]
Scroll down to about the middle of the linked page here where it says If you use Mozilla Thunderbird" and Option 1 is all you need as instructions from this page. Ignore the rest. https://support.microsoft.com/en-us/office/modern-authentication-methods-now-needed-to-continue-syncing-outlook-email-in-non-microsoft-email-apps-c5d65390-9676-4763-b41f-d7986499a90d
STEP [2]
On the following linked page you will see chevrons for topic drop down instructions you
will need to follow regarding the permissions settings in your outlook account you see
when viewing your emails in a web browser NOT in your email client app, but online
as if you were using a computer in a library or internet cafe to access your mail.
If you get any security challenges by Microsoft popups for confirming identity by
text or email or 2 step identification then cooperate with with the bot that is tasked
to verify "Is it really you?" and confirm your permissions settings. https://support.microsoft.com/en-us/office/pop-imap-and-smtp-settings-for-outlook-com-d088b986-291d-42b8-9564-9c414e2aa040
After you have made your server settings in both the Thunderbird client app and
permission settings to enable access within the outlook account, then connection
should sync okay and you should have no issues. Server names and ports have to
be correct for the type account POP or IMAP. When you believe you have gotten
the settings correct, close the browser to your outlook account. I would even close
and restart the Thunderbird app, even though I think the settings changes will
occur without closing and reopening these apps, it won't hurt. Send yourself a
test message from another email account like gmail to confirm the outlook
account is accepting access by Thunderbird. If your test message is received,
then everything is good to go and you are set.