This issue is addressed in GarageBand for iOS 1.2.1. Update GarageBand for iOS to the latest version by tapping the App Store on your device and then tapping Updates.
GarageBand for iOS: May be unable to share to SoundCloud
You may be unable to share a song to SoundCloud when you use the Connect With Facebook feature. You may see a message that states "Safari cannot open the page because the address is invalid."
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