An error is reported when performing pod install: (reason for this problem: cocoapods 1.8 switches the CDN to the default spec repo source)

[!] CDN: trunk Repo update failed - 56 error(s):
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1. Check the version number to see if the version is 1.8 or later

pod --version

2. Remove trunk

pod repo remove trunk

3. Enter this directory

cd ~/.cocoapods/repos

4. Execute command

git clone --depth 1 https://github.com/CocoaPods/Specs.git master

5. Here you are. Just execute pod install again.