composer 安装不上

Question

Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 24 installs, 0 updates, 0 removals
  - Installing topthink/framework (v5.0.20): Downloading (100%)
  - Installing symfony/polyfill-mbstring (v1.8.0): Downloading (failed)
Downloading (connecting...)
Downloading (failed)    Failed to download symfony/polyfill-mbstring from dist:
The "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/3296adf6a645
4a050679cde90f95350ad604b171" file could not be downloaded: failed to open strea
m: HTTP request failed!
    Now trying to download from source
  - Installing symfony/polyfill-mbstring (v1.8.0): Cloning 3296adf6a6


  [RuntimeException]
  Failed to clone https://github.com/symfony/polyfill-mbstring.git via https,
   ssh protocols, aborting.

  - https://github.com/symfony/polyfill-mbstring.git
    Cloning into 'E:\wwwroot\fastadmin\vendor\symfony\polyfill-mbstring'...
    fatal: unable to access 'https://github.com/symfony/polyfill-mbstring.git
  /': Empty reply from server

  - [e-mail]:symfony/polyfill-mbstring.git
    Cloning into 'E:\wwwroot\fastadmin\vendor\symfony\polyfill-mbstring'...
    Host key verification failed.
    fatal: Could not read from remote repository.

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


install [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--no-c
ustom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--no-suggest
] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative]
 [--apcu-autoloader] [--ignore-platform-reqs] [--] [<packages>]...

镜像都是用国内的 就是安装不上下载失败 求解啊

Answer 1

换源，https://pkg.phpcomposer.com/

Answer 2

再换源，https://packagist.laravel-chi...