hi, bro, I have encounter the same problem, the sandbox page display nothing but white page. Are you in mainland area?

I had the some error recently, but just see this error once

I found out how to solve the Library 'BVLinearGradient' not found because I open the ios proj via AwesomeProject.xcodeproj, but actually I have to open the proj via AwesomeProject.xcworkspace then product->build, after a while, build succeed That's All

I found a method to solve the problem partially, in Xcode, User Script SandBoxing set to NO then I can run the React native project correctly