Issue: Thunderbird fails at the authentication stage of adding an 0365 Exchange email account. Your email address and password are confirmed and correct. The issue is Exchange requires an Active Sync or EWS Exchange Web Services connection which ThunderBird doesn’t natively support.

Solution – install the ExQuilla for Microsoft Exchange and Exchange EWS Provider Add-Ons. ExQuilla connects email and contacts, Exchange EWS Provider connects the calendar.

Step 1 Email and Contacts – Install & Configure ExQuilla

Tools > Add-Ons
Search for and download the ExQuilla for Microsoft Exchange add-on. It does not show up until you click “show all results”
Go to Tools > ExQuilla for Microsoft Exchange
Enter your email address and password (check “remember password”
Click the “do auto discover” button which should automatically configure your account via Exchange Web Services (EWS) – https://outlook.office365.com/EWS/Exchange.asmx
Click Next
Done!
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If you encounter any issues (went smoothly here!)
1. Detailed install steps from ExQuilla
2. Detailed Exchange config steps from ExQuilla

Step 2 Calendar – Download, install & configure Exchange EWS Provider

Download the Exchange EWS Provider XPI file – exchangecalendar-vx.x.0.xpi
Install: Tools > Add-Ons > Gear icon > Install Add-On from File…
Select the the XPI file > click Open > click Install Now > Restart ThunderBird
Create new Calendar: File > New > Calendar
Choose On the Network
Choose Microsoft Exchange
Enter name and email address
Choose Hosted Exchange
Configure New Calendar
1. * The “Use Exchange’s autodiscovery function” did not work for me
2. Enter Server URL: https://outlook.office365.com/EWS/Exchange.asmx
3. Enter username and email address (username is typically your full email address)
4. Click Check Server and Mailbox
Click Next & Finish
Enjoy!

ExQuilla - Add Exchange Account Email — ExQuilla – Add Exchange Account Email

ExQuilla - Add Exchange Account Email — ExQuilla – Add Exchange Account Email

ExQuilla - Add Exchange Account Email - AutoDiscover — ExQuilla – Add Exchange Account Email – AutoDiscover

ExQuilla - Add Exchange Account Email - Done — ExQuilla – Add Exchange Account Email – Done

Exchange EWS Provider - Install From File — Exchange EWS Provider – Install From File

Exchange EWS Provider - Name & Email - Done — Exchange EWS Provider – Name & Email – Done

Exchange EWS Provider - Name & Email — Exchange EWS Provider – Name & Email

Exchange EWS Provider - On Network — Exchange EWS Provider – On Network

Exchange EWS Provider - Name & Email - Microsoft Exchange — Exchange EWS Provider – Name & Email – Microsoft Exchange

Exchange EWS Provider - Name & Email - Hosted Exchange — Exchange EWS Provider – Name & Email – Hosted Exchange

Exchange Add-Ons - ThunderBird — Exchange Add-Ons – ThunderBird