Apple Beta Software Program members should be advised they may face issues and crashes of the MoviePass app when on the beta iOS 12. MoviePass plans to offer support for iOS 12 once it is out of Beta and released to the public. Just as Apple does, we highly advise against installing iOS 12 Betas on your personal or non-developer device. We do not currently have any workarounds or fixes for these crashes.
MoviePass advises those users who are affected to consider downgrading from the iOS 12 Beta back to iOS 11. Instructions from Apple on how to do this are located here: https://support.apple.com/en-us/HT203282