Is there any outlook about this ticket? It is one of the most popular questions about sourcetree on stackoverflow:

https://stackoverflow.com/q/45622960/1667868

I was able to get it working with System Git, but Embedded Git isn't working. The embedded git version is older than system git.

Tools > Options > Git > Use System Git

My System Git version - 2.16.1

Even with the correct credentials, it fails to pull, fetch, commit, nothing is working.

I am facing the same issue 2.4.8. SourceTree continues to ask for credential even though I entered the correct info. I have already updated embedded git

I have just downloaded latest version (2.4.8.0) of sourcetree, and updated embedded git (after many unsuccessful attempts) (embedded git version - 2.15.1), but unable to resolve authentication error. 

This is such a stupid bug. MacOS High Sierra doesn't have a "Tools" menu. You can get to the Git options screen by going to Preferences > Git, but once there you don't have any options to "Update Embedded Git". Every push is failing authentication from Sourcetree.

This is not resolved. The install is still not working without updating the Embedded Git. Waste of half an hour finding this bug.

Tools > Options > Git > Update Embedded Git

Yes, updating worked for me too. Many thanks to those who suggested the solution.

Just ran into this problem.  Updating the embedded git worked, but it was odd - just after I clicked the Update button, I noticed that the current embedded git version in a fresh install of the latest SourceTree for Windows (v. 2.3.5.0) was 2.8 something (didn't catch anything after the 2.8).  After the update, the embedded git version is now:  2.14.1/LibGit2Sharp 0.24.0 + git.

I also had to revoke the OAuth token for the SourceTree application after deleting the credentials in the local file system as explained above. You can delete the token in your Bitbucket user account: https://bitbucket.org/account/user/\{your user name}/api