Composer install 时候关于 symfony 没有权限的问题

我把我之前的blog拉取下来。执行composer install的时候报下面这个错：

报错内容 我用MarkDown贴一下：

[RuntimeException]                                                                                                                      
  Failed to clone https://github.com/symfony/polyfill-ctype.git via https, ssh protocols, aborting.                                       
  - https://github.com/symfony/polyfill-ctype.git                                                                                         
    fatal: unable to access 'https://github.com/symfony/polyfill-ctype.git/': Peer reports incompatible or unsupported protocol version.  

  - git@github.com:symfony/polyfill-ctype.git                                                                                             
    Permission denied (publickey).                                                                                                        
    fatal: Could not read from remote repository.                                                                                         

    Please make sure you have the correct access rights                                                                                   
    and the repository exists.

git@github.com:symfony/polyfill-ctype.git

这个类没有权限拉取。可是这个类不是 laravel composer 里的类吗？，所以这个错报的我很迷茫。有没有朋友遇到过这个问题，麻烦解答一下。蟹蟹啦