A knowledge base article about bSecure GlobalProtect VPN: Apple iOS 12 (iPhones, iPads) Fails to Connect provided by the UC Berkeley IT Service Hub - Knowledge Portal
GlobalProtect versions 4.1.x and before do not support Apple iOS 12.
For users of devices running iOS 11 and older please install GlobalProtect Legacy
For users of devices running iOS 12 and newer please install GlobalProtect.