我无法让我的作曲家安装或作曲家更新工作，导致以下错误。 如果我运行composer install或composer update，则需要很长时间才能抛出错误。
当我运行此命令时：
composer update
我得到以下输出：
Loading composer repositories with package information
[Composer\Downloader\TransportException]
The "https://packagist.org/packages.json" file could not be downloaded: failed to open stream: Connection timed out
update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--no-suggest] [--with-dependencies] [--with-all-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [-i|--interactive] [--root-reqs] [--] [<packages>]...
composer diagnose的输出：
Checking platform settings: OK
Checking git settings: OK
Checking http connectivity to packagist: WARNING
[Composer\Downloader\TransportException] The "http://packagist.org/packages.json" file could not be downloaded: failed to open stream: Connection timed out
Checking https connectivity to packagist: WARNING
[Composer\Downloader\TransportException] The "https://packagist.org/packages.json" file could not be downloaded: failed to open stream: Connection timed out
Checking github.com rate limit: OK
Checking disk free space: OK
Checking pubkeys:
Tags Public Key Fingerprint: 57815BA2 7E54DC31 7ECC7CC5 573090D0 87719BA6 8F3BB723 4E5D42D0 84A14642
Dev Public Key Fingerprint: 4AC45767 E5EC2265 2F0C1167 CBBB8A2B 0C708369 153E328C AD90147D AFE50952
OK
Checking composer version: OK
Composer version: 1.6.5
PHP version: 7.0.30-1+ubuntu16.04.1+deb.sury.org+1
PHP binary path: /usr/bin/php7.0
我的系统配置：
我搜索了很多，但没有为我找到合适的解决方案，请帮我解决一下
由于