Undefined symbols for architecture armv7: “_OBJC_CLASS_$_FIRApp”

Question

I am integrating Firebase in my app according to the instructions and added [FIRApp configure]; in the code however, while compiling the app I am getting the following error

Answer 1

Did CocoaPods write any warnings due to pods installation? I fixed a similar issue by setting OTHER_LDFLAGS build settings to $(inherited) flag.