Build error - Undefined symbols for architecture x86_64: "_OBJC_CLASS_$_CoronaAppDelegate"

Solar2D iOS
#1

I followed step by step the installation tutorial to integrate Corona on a project based on http://docs.coronalabs.com/coronacards/ios/setup.html and I find the following error.

Undefined symbols for architecture x86_64:
  “_OBJC_CLASS_$_CoronaAppDelegate”, referenced from:
      objc-class-ref in CoronaCards(Rtt_IPhoneRuntimeDelegate.o)
ld: symbol(s) not found for architecture x86_64
 

What should I do to solve?

Thanks.

#2

This appears to be a duplicate thread. Lets continue the conversation here:
 

https://forums.coronalabs.com/topic/73533-undefined-symbols-for-architecture-x86-64-objc-class-coronaappdelegate-referenced-from-objc-class-ref-in-coronacardsrtt-iphoneruntime/

Rob

#3

This appears to be a duplicate thread. Lets continue the conversation here:
 

https://forums.coronalabs.com/topic/73533-undefined-symbols-for-architecture-x86-64-objc-class-coronaappdelegate-referenced-from-objc-class-ref-in-coronacardsrtt-iphoneruntime/

Rob