The first time I entered the password for a pull pull request from Github with Eclipse (EGit) I probably mistyped it. Now it automatically uses this password and everytime I try to make pull / fetch or push to upstream I get a not authorized error. But I can't find anywhere how to fix the wrong credentials. Anyone who knows?
I think Preferences > General > Security > Secure Storage > Clear Passwords
which clears everything. Or you can also selectively delete stuff from <user directory>\.eclipse\org.eclipse.equinox.security\secure_storage