SourceTree fails to connect to Visual Studio Team Services when the new Azure DevOps URL is in use.
Using "*https://dev.azure.com/ACCOUNT*" fails with error "" when using "".
Using "*https://ACCOUNT.visualstudio.com*" works fine. (this is the old domain, new accounts are not using this URL anymore)
Capturing packets using FIDDLER I noticed that when using "https://dev.azure.com/ACCOUNT*" SourceTree tries to connect to "*app.vssps.visualstudio.com" instead of the given URL.
When using " https://ACCOUNT.visualstudio.com", SourceTree connects properly to that URL.