No OAuth2 prompt when trying to add outlook.com calendar

[ProvocaTeach]

Your environment

TbSync version: 4.11
EAS-4-TbSync version: 4.12
Thunderbird version: 128.5.1esr (64-bit)

Expected behavior

OAuth2 prompt appears, I enter my outlook.com credentials, and the calendar is added.

Actual behavior

The prompt window shows no content for a long time…

…then gives a “Hmm. We’re having trouble finding that site” error.

Steps to reproduce

1. Click “TbSync: Idle” in the bottom-right corner. Choose Account actions / Add new account / Exchange ActiveSync.
2. Select Microsoft Office 365 as the account type.
3. Enter an account name and an outlook.com email address.
4. Click “Add account.” You should see the (blank) prompt window open.
5. Wait about 1 minute. You should see the “Hmm. We’re having trouble finding that site” message.

To help resolving your issue, enable debug logging (TbSync Account Manager -> Help) and send me the debug.log via e-mail (use the title of your issue as subject of the email). (Done!)

[ghost-from-the-past]

I you are under Windows 11 try to use Google Chrome as your default internet browser.

I was having problems to connect to outlook.office365.com (OAuth2 problems) because I was having Firefox as my default internet browser, there is something fishy with Firefox and OAuth2 under Windows 11 ...

I have also TB (the same version) running on my MacOS laptop and on another Ubuntu 24.10 desktop, there I didn't find any problem using firefox, only under my Windows 11 machine