Background 

Microsoft first announced that Basic Authentication for most Exchange Online Services will be turned off on 13 October 2020. In response to the COVID-19 crisis and knowing that priorities of their customers changed, they have decided to postpone disabling Basic Authentication in Exchange Online for those tenants still actively using it until the second half of 2021.

Once Basic Authentication was disabled, you must use clients that support Modern Authentication to access their mailbox.  With modern authentication, your credential will not be sent to O365 which provide an enhanced the security and access reliability. Instead, you will be directed to CUHK Login. If you have enrolled DUO 2FA, you will be asked to confirm to enter 2FA for a better email protection.  

The Impact

Services no longer support Basic Authentication ends: 

• POP 
• IMAP 
• Exchange Web Services (for Outlook client) 
• Exchange ActiveSync (EAS) (for most mobile client) 
• Remote PowerShell (for technical support) 

Services still support Basic Authentication after the second half of 2021: 

• SMTP  

Switch to Email Clients that Support Modern Authentication 

You must use the following email clients that support Modern Authentication. Otherwise, you cannot send/receive email when Basic Authentication ends. 

• OWA (Outlook on the web) 
• Outlook 2013 or later (Outlook 2013 requires a registry key change) 
• Outlook 2016 for Mac or later 
• Outlook for iOS and Android 
• Mail for iOS 12 or later 
• Microsoft Teams 

Check related user guides for usage details. 

Email Clients NOT support Modern Authentication 

These clients do not support Modern Authentication and will no longer work from second half of 2021: 

• Old Outlook clients or Outlook clients that did not enable Modern Authentication 
• Gmail App for mobile 
• Exchange ActiveSync clients that do not support Microsoft Modern Authentication such as: 
  • Most Android Mail/Schedule/Contact Apps 
• IMAP/POP clients that do not support Microsoft Modern Authentication such as: 
  • Most IMAP/POP mail client such as Thunderbird and Eudora
  • Using Gmail to manage Exchange Online Mailbox 

Reminder:

• For clients like Thunderbird, Eudora, etc, please check if your client’s developer offers any solution that supports Modern Authentication. You can considering upgrade if there is. Otherwise, please switch to use the latest version of outlook or web outlook so as to continue accessing your emails when Microsoft ends its basic authentication support.

References: 

• Basic Auth and Exchange Online –  April 2020 Update: 

https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-and-exchange-online-april-2020-update/ba-p/1275508 

• Improving Security – Together: 

https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Improving-Security-Together/ba-p/805892