You might want to open the
.git\config as a plain file from Visual Studio and edit its contents.
You'll see that there is a section defining the remote called
url = git://foo.org/blah.git
fetch = +refs/heads/*:refs/remotes/origin/*
If you are using HTTPS (SSL) as a transport layer, then you might want to add:
sslVerify = false
if you are using a self-issued SSL certificate on the server.