iOS build fails: linker fails to find symbols from system frameworks

iOS builds constantly fails, because linker fails to find symbols from system frameworks. E.g.:

9776: [xcode] Undefined symbols for architecture armv7:
9777: [xcode] “_SLServiceTypeTwitter”, referenced from:
9778: [xcode] -[ADCDeviceData initInfo] in AdColony(ADCDeviceData.o)
9779: [xcode] -[ADCMRAIDCompanionAd getCanonicalSocialName:] in AdColony(ADCMRAIDCompanionAd.o)
9780: [xcode] “OBJC_CLASS_EKEventEditViewController", referenced from: 9781: [xcode] objc-class-ref in GoogleMobileAds(flat-armv7) 9782: [xcode] "_SLServiceTypeSinaWeibo", referenced from: 9783: [xcode] -[ADCDeviceData initInfo] in AdColony(ADCDeviceData.o) 9784: [xcode] -[ADCMRAIDCompanionAd getCanonicalSocialName:] in AdColony(ADCMRAIDCompanionAd.o) 9785: [xcode] "_OBJC_CLASS__MFMailComposeViewController”, referenced from:
9786: [xcode] objc-class-ref in AdColony(ADCDeviceData.o)
9787: [xcode] objc-class-ref in AdColony(ADCMRAIDCompanionAd.o)
9788: [xcode] objc-class-ref in libHeyzapAds.a(HZMediationTestActivityViewController.o)
9789: [xcode] objc-class-ref in GoogleMobileAds(flat-armv7)
9790: [xcode] “OBJC_CLASS_MFMessageComposeViewController", referenced from: 9791: [xcode] objc-class-ref in AdColony(ADCDeviceData.o) 9792: [xcode] objc-class-ref in AdColony(ADCMRAIDCompanionAd.o) 9793: [xcode] objc-class-ref in GoogleMobileAds(flat-armv7) 9794: [xcode] "_SLServiceTypeFacebook", referenced from: 9795: [xcode] -[ADCDeviceData initInfo] in AdColony(ADCDeviceData.o) 9796: [xcode] -[ADCMRAIDCompanionAd getCanonicalSocialName:] in AdColony(ADCMRAIDCompanionAd.o) 9797: [xcode] ___46-[ADCMRAIDCompanionAd MRAIDCommandSocialPost:]_block_invoke in AdColony(ADCMRAIDCompanionAd.o) 9798: [xcode] (maybe you meant: _fbsdkdfl_SLServiceTypeFacebook) 9799: [xcode] "_OBJC_CLASS__SLComposeViewController”, referenced from:
9800: [xcode] objc-class-ref in AdColony(ADCDeviceData.o)
9801: [xcode] objc-class-ref in AdColony(ADCMRAIDCompanionAd.o)

The same project locally builds normally.

Cloud build settings:
Unity 5.3.4p3
Xcode 7.2

Which version of Xcode are you building with in Cloud Build? Currently, if you have “latest xcode” selected it still uses Xcode 7.0, but you can manually select Xcode 7.2 in the signing options for that build target.

I have already manually selected Xcode 7.2.
But previously I had the same issue with Xcode 7.0.

Locally I build with Xcode 7.3.

Sorry for being slow getting back to this - can you PM me a link to your project in cloud build so I can look into it?