SourceTree Enterprise: "failed to check login for user"

Issue description

I installed SourceTree Enterprise and attempted to login to my local Bitbucket Server installation. The login fails with the message "failed to check login for user [

{username}]".

The log has the following entries:
ERROR [timestamp] [1] [SourceTree.Exceptions.RemoteHostException] [.ctor] - Insufficient authentication credentials
ERROR [timestamp] [1] [SourceTree.Exceptions.RemoteHostException] [.ctor] - Failed to check login for user [{username}

]

The root URL ( "https://{server}.{domain}/{context}/" ), username and password are the same ones I use when successfully logging into Bitbucket in Internet Explorer on the same PC.

My username does not include any special characters such as the '@' symbol.

I have tried the suggestions in the following:
https://community.atlassian.com/t5/Sourcetree-questions/Getting-this-error-quot-Something-went-wrong-while-attempting-to/qaq-p/805220
https://community.atlassian.com/t5/Sourcetree-questions/Looking-for-more-details-on-login-error/qaq-p/802237

What additional authentication credentials should be supplied, and how?

It seems rather over the top to raise a bug when I suspect all I'm missing is some documentation on how to set SourceTree up correctly, but I can't seem to find anything and the community question I raised hasn't received any responses (https://community.atlassian.com/t5/Sourcetree-questions/SourceTree-Enterprise-quot-failed-to-check-login-for-user-quot/qaq-p/810106).

Cause

As of Sourcetree for Windows v2.5.5, it appears that the login to local Bitbucket Server instance will fail with "failed to check login for user [

{username}

]" when Bitbucket Server is on a context path (e.g. https://internal.mysite.com/bitbucket).

Work around

1. Use Sourcetree for Windows v2.4.8.0; or
2. Temporarily drop the context path by changing the Base URL of Bitbucket to say just https://internal.mysite.com. e.g.
   • Update reverse proxy from "/bitbucket" -> http://<bitbucketserver>:<port>/bitbucket to "/" -> http://<bitbucketserver>:<port>/
   • Deleted the server.context-path line out of bitbucket.properties
   • Updated the Bitbucket Administration » Base URL to just https://internal.mysite.com
   • Restart Bitbucket
   • Perform the login into Sourcetree and hopefully it succeeds this time
   • Once all the users have installed Sourcetree, you can revert Bitbucket back to the Context Path /bitbucket
   • Now that you are in Sourcetree, you should be able to Clone a REPO from https://internal.mysite.com/bitbucket and do all things branch, commit, push, pull, etc...