admob unity plugin ios Undefined symbols for architecture arm64:

I have a project that includes Admob unity plugin , i build it for ios. I followed the instruction below using the cocoa pods method to set the plugin up.

https://developers.google.com/admob/ios/quick-start#streamlined_using_cocoapods

i build the project in Xcode 7 but get build errors below. I been trying to get it to build for a day, any help appreciated.

Undefined symbols for architecture arm64:
"_kGADAdSizeSmartBannerLandscape", referenced from: -[GADUBanner initWithSmartBannerSizeAndBannerClientReference:adUnitID:adPosition:] in GADUBanner.o
"OBJC_CLASS$_GADBannerView", referenced from: objc-class-ref in GADUBanner.o "OBJC_CLASS$_GADRequest", referenced from: objc-class-ref in GADURequest.o "OBJC_CLASS$_GADInterstitial", referenced from: objc-class-ref in GADUInterstitial.o
"_kGADAdSizeSmartBannerPortrait", referenced from: -[GADUBanner initWithSmartBannerSizeAndBannerClientReference:adUnitID:adPosition:] in GADUBanner.o
"OBJC_CLASS$_GADExtras", referenced from: objc-class-ref in GADURequest.o "_GADAdSizeFromCGSize", referenced from: -[GADUBanner initWithBannerClientReference:adUnitID:width:height:adPosition:] in GADUBanner.o ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation)