今天更新cocoapods版本的时候，安装会报出一个奇怪的错误

sudo gem install cocoapods

ERROR: Could not find a valid gem 'cocoapods' (>= 0), here is why:
Unable to download data from https://gems.ruby-china.org/ - bad response Not Found 404 (https://gems.ruby-china.org/specs.4.8.gz)

通过查找原因发现：sources 里面镜像链接 https://gems.ruby-china.org 被弃用：

Screen Shot 2019-03-06 at 4.49.04 PM.png

需要重新换一下源：

gem sources --remove https://gems.ruby-china.org/
gem sources --add https://gems.ruby-china.com/
gem sources --list                               

*** CURRENT SOURCES ***

https://gems.ruby-china.com/

然后重新安装一下即可

sudo gem install cocoapods

如果有人遇到类似的问题，希望对你有所帮助。