What did you do?
I add Firebase into multiple target.

What did you expect to happen?
Firebase pods will installed correctly

What happened instead?
The response after pod install is just JSON::ParserError - 767: unexpected token at ''. But when I didn't include Firebase, installation going well

JSON::ParserError - 767: unexpected token at ''

解決辦法

gem list --local | grep cocoapods
sudo gem uninstall cocoapods
sudo rm -rf ~/.cocoapods
sudo gem install cocoapods
cd (PROJECT DIRECTORY)
pod init
(put cocoapod in podfile)
pod install
and worked, I don't know why, but worked