前提
ssh -T git@github.com 命令连接正常；
git clone、git pull 正常，github页面 `Settings/SSH and GPG keys` 确认已添加过本地ssh公钥。
注：git clone 出现类似问题的，可以考虑先移步git clone出现 fatal: unable to access 'https://github.com/...'的解决办法(亲测有效)_明天也要加油鸭的博客-CSDN博客
$ ssh -T git@github.com Hi birdflyi! You've successfully authenticated, but GitHub does not provide shell access.
问题
git push 失败，提示fatal: 发送请求时出错，并报告不再支持密码认证方式，需要使用personal access token替代密码认证方式（然而前面已确认github页面添加过本地的ssh公钥）。
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main) $ git push --set-upstream origin main fatal: 发送请求时出错。 fatal: 请求被中止: 未能创建 SSL/TLS 安全通道。 fatal: 发送请求时出错。 fatal: 请求被中止: 未能创建 SSL/TLS 安全通道。 remote: Support for password authentication was removed on August 13, 2021. Please use a personal access token instead. remote: Please see https://github.blog/2020-12-15-token-authentication-requirements-for-git-operations/ for more information. fatal: Authentication failed for 'https://github.com/birdflyi/Research-Methods-of-Cross-Science/'
remote报错：2021年8月13日，移除了对密码验证方式的支持。请改用个人访问令牌。
官方的解释：https://github.blog/changelog/2021-08-12-git-password-authentication-is-shutting-down/
已有相关博客解释说明此变化，并给出了配置github上的ssh Keys的方法[1]：GitHub不再支持密码验证解决方案：SSH免密与Token登录配置 - 爱码网
此博客还包含使用令牌的好处说明：GitHub不再支持密码验证解决方案：SSH免密与Token登录配置 - 爱码网
问题特征特殊情况的特征在于：git remote -v 显示配置的url是http或https协议的，而配置的ssh需要使用git@github.com形式的ssh协议url。
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main) $ git remote -v origin https://github.com/birdflyi/Research-Methods-of-Cross-Science (fetch) origin https://github.com/birdflyi/Research-Methods-of-Cross-Science (push)解决方案
综上，github的ssh Keys配置（详见[1]不再赘述）没有问题的情况下，将remote的url改成ssh所需的git@github.com形式即可。
即：
$ git remote remove origin
$ git remote add origin git@github.com:birdflyi/Research-Methods-of-Cross-Science
实践中会有一些额外的操作才能使用默认的 git push 命令：
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git remote -v
origin https://github.com/birdflyi/Research-Methods-of-Cross-Science (fetch)
origin https://github.com/birdflyi/Research-Methods-of-Cross-Science (push)
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git remote remove origin
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git remote add origin git@github.com:birdflyi/Research-Methods-of-Cross-Science
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git remote -v
origin git@github.com:birdflyi/Research-Methods-of-Cross-Science (fetch)
origin git@github.com:birdflyi/Research-Methods-of-Cross-Science (push)
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git push
fatal: The current branch main has no upstream branch.
To push the current branch and set the remote as upstream, use
git push --set-upstream origin main
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git push --set-upstream origin HEAD:main
Everything up-to-date
branch 'main' set up to track 'origin/main'.
Adan@Adan-PC MINGW64 /e/gitRepo/Research-Methods-of-Cross-Science (main)
$ git push
Everything up-to-date
