Im trying to push to github with sourcetree but get the following error:
git -c diff.mnemonicprefix=false -c core.quotepath=false push -v --tags origin
I typed the wrong username (email address) when pushing and what worked for me was:
Open KeyChain Access search for SourcTree delete the 'login' item
Then go to Sourcetree > Preferences > Advanced and delete the default usernames that includes the wrong email address.