新手第一次用Git，按CSDN上面找的教程想要远程提交本地到GitHub的时候报错了，翻了一遍GitHub上面的手册也没找到解决方案。
$ git remote add origin git@github.com:Cell1344/Note-on-Tao-Zheuan-real-analysis.git
git branch -M main
git push -u origin main
error: remote origin already exists.
fatal: unable to access 'https://github.com/Cell1344/Note-on-Tao-Zhexuan-real-analysis.git/': Failed to connect to github.com port 443 after 2084 ms: Connection refused
想请教一下这是什么问题，要如何解决
（输入是复制GitHub创建空存储库页面里面的内容）
$ git remote add origin git@github.com:Cell1344/Note-on-Tao-Zheuan-real-analysis.git
git branch -M main
git push -u origin main
error: remote origin already exists.
fatal: unable to access 'https://github.com/Cell1344/Note-on-Tao-Zhexuan-real-analysis.git/': Failed to connect to github.com port 443 after 2084 ms: Connection refused
想请教一下这是什么问题，要如何解决
（输入是复制GitHub创建空存储库页面里面的内容）
