As of November 17, 2020 my Outlook desktop app client started to have authentication problems for my hotmail.com / outlook.com emails and I though initial it was due to outdated setting see below. But that was not it.
Seems my VPN is randomly choosing countries on start-up to pass thru even though I selected Canada only by default. However, if you are connecting from different countries or IP addresses (if you are a mobile worker for example) you will like trigger the following warning.
Update 11-Feb-21 - How to check Outlook desktop app account connection problems with Outlook.com or Hotmail.com blocked, stopped, not working, authentication problems
outlook.office365.com is complaining of suspicious activity and has temporarily blocked access.
Solution : Login into outlook.com with hotmail.com or outlook.com through your browser into your account will work in your Outlook client.
Double check these new server settings as well.
There are new server settings, and available here for reference : https://support.microsoft.com/en-us/office/pop-and-imap-email-settings-for-outlook-8361e398-8af4-4e97-b147-6c6c4ac95353
New server settings
Outlook.com Hotmail.com Live.com | IMAP Server: outlook.office365.com Port: 993 Encryption: SSL/TLS | POP Server: outlook.office365.com Port: 995 Encryption: SSL/TLS | SMTP Server: smtp.office365.com Port: 587 Encryption: STARTTLS |
Goto E-mail accounts and edit your existing connection to use the above setting, below is for POP/SMTP settings. Change to new setting in above table
Use TLS, if you cannot choose both under "More settings....."