Cannot authenticate with visual studio project

[Wendy Dang]

I have put my local repo into source tree but when I try to do a pull to update my branches with what is on the remote repo, I get an authentication error and some key errors:

git -c diff.mnemonicprefix=false -c core.quotepath=false --no-optional-locks fetch origin
fatal: ArgumentException encountered.
   An item with the same key has already been added.fatal: ArgumentException encountered.
   An item with the same key has already been added.fatal: Authentication failed for 'https://myteamname.visualstudio.com/pathforthingy/'
Completed with errors, see above.

My account seems to be unable to link up to my Microsoft account, which has permissions to use this repo. 

[minnsey]

There is a bug in Git Credential Manager for Windows, GCMW, <1.18.3.

The GCMW is bundled with Git for Windows.

Best workaround for now is the install Git 1.19.1 https://git-scm.org and then install GCMW 1.18.3 https://github.com/Microsoft/Git-Credential-Manager-for-Windows/releases/tag/v1.18.3, then in Sourcetree Tools/Options/Git tab select that Git install as a System Git