The Git credential cache runs a daemon process that caches your credentials in memory and hands them out on demand. So killing your git-credential-cache--daemon process throws all these away and results in re-promoting you for your password if you continue to use this as the cache.helper option.
You could also disable the use of the Git credential cache using git config --global --unset credential.helper. Then reset this, and you would continue to have the cached credentials available for other repositories (if any). You may also need to do git config --system --unset credential.helper if this has been set in the system configuration file.