ポッドのインストールを実行すると、次のエラーが発生しました。
[!] CDN: trunk Repo update failed - 4 error(s):
CDN: trunk URL couldn't be downloaded: https://cdn.jsdelivr.net/cocoa/Specs/c/7/9/Reachability/3.0.0/Reachability.podspec.json Response: Timeout was reached
CDN: trunk URL couldn't be downloaded: https://cdn.jsdelivr.net/cocoa/Specs/c/7/9/Reachability/3.1.0/Reachability.podspec.json Response: Timeout was reached
CDN: trunk URL couldn't be downloaded: https://cdn.jsdelivr.net/cocoa/Specs/c/7/9/Reachability/3.1.1/Reachability.podspec.json Response: Timeout was reached
CDN: trunk URL couldn't be downloaded: https://cdn.jsdelivr.net/cocoa/Specs/c/7/9/Reachability/3.2/Reachability.podspec.json Response: Timeout was reached解決：
cdn ソースをソース「https://github.com/CocoaPods/Specs.git」に置き換えます。
ステップ：
1. ポッドファイルの先頭にソース「https://github.com/CocoaPods/Specs.git」を追加します
2. ターミナルの下で pod repo Remove train を実行してトランクを削除します
3. 再ポッドのインストール