To make EasyAR to be built and ran successfully on iOS,
1. In XCode project, add 'libc++.tbd' in General>Linked Frameworks and Libraries
2. Disable Bitcode by selecting 'No' on Build Settings>Build Options>Enable Bitcode.
You should look for the log output to find error. It works fine for me using Unity 2019.1.0f1 + EasyAR 2.3.0.