SourceTree error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
Check Tools > Options > Git in SourceTree, if you're using Use Embedded Git, you can see the git version is 1.9.5 which is old, latest version of git is 2.16.2.
So click Use System Git, if you install the newer version of git, after Use system Git it'll show newer version, then try to clone again it should work fine.
Also see another answer HERE.
I had the same problem and my fix was:
1.update git to the latest version
2.in command line check your tls version with command: git config http.sslVersion
3.if the version is tlsv1.0 than you have to update it to tlsv1.2 with command:
- git config --global --unset http.sslVersion
- git config --global --add http.sslVersion tlsv1.2
and than the error won't be present anymore