composer下载依赖，报错

Question

使用composer下载依赖时，总是报：由于连接方在 一段时间后没有正确答复或连接的主机没有反应，连接尝试失败

相关代码

PS E:wwwroot3dnote> composer require yiisoft/yii2-gii
Using version ^2.0 for yiisoft/yii2-gii
./composer.json has been updated
Loading composer repositories with package information
The "https://packagist.phpcomposer.com/packages.json" file could not be downloaded: failed to open stream: 由于连接方在 一段时间后没有正确答复或连接的主机没有反应，连接尝试失败。

https://packagist.phpcomposer... could not be fully loaded, package information was loaded from the local cache and may be out of date