Steps to reproduce the S2S issue:

1. Select GoogleDebugApp as build target in your xcode
2. Launch app on your device/simulator
3. Search "demo error" in the console output to see the error message

Steps to test with S2S banner:

1. Go to ViewController.swift in the GoogleDebugApp project
2. comment: googleQueryInfoFetcher?.fetch(completeListener: self) line to disable S2S load ad
3. uncomment: gadBannerLoader?.loadC2SBannerView(... line to enable client to server load ads
4. Select GoogleDebugApp as build target in your xcode
5. Launch app on your device/simulator, you should be able to see the banner ad display.