iOS - Facebook Login Error - Unknown Error building URL (com.facebook.sdk.core error 3)

Question

I am using Facebook login for my iOS app being developed for iOS 8 and onwards. (Latest Facebook SDK is being used)

I have followed all the essential steps described by

Answer 1

This is a Facebook SDK bug in version 4.39.0 which is causing this error. In order to solve this bug, simply downgrade both CoreKit and LoginKit to 4.38.0, clear derived data as well as clean build folder (CMD + OPTION + SHIFT + K). Whereas 4.38.1 also works fine.

pod 'FBSDKCoreKit', '~> 4.38.0'
pod 'FBSDKLoginKit', '~> 4.38.0'

If you are using FacebookCore and FacebookLogin then do like the following.

pod 'FacebookCore'
pod 'FacebookLogin'
pod 'FBSDKCoreKit', '~> 4.38.0'
pod 'FBSDKLoginKit', '~> 4.38.0'