can't connect to github

[KidsBookOutlet]

When I open a repository in SourceTree it sees all my history, and changes but will not push or pull to//from GitHub. I also have GitHub desktop which has no problem communicating with github from the same repository.

I keep getting askpass errors, no matter which login format i use (email, user name).

git -c diff.mnemonicprefix=false -c core.quotepath=false --no-optional-locks fetch origin
Logon failed, use ctrl+c to cancel basic credential prompt.
Completed with errors, see above.

my workaround is that I do all pulls and pushes from GitHub Desktop and my work in sourceTree.

Any suggestions?

AThanks

AQbbott