There are a significant number of complaints about this on the App Store under recent reviews and downdetector is also noting significant reports. If you launch the app only a blank white screen appears and will crash the app if left open long enough. I contacted them by Twitter and phone to report the issue but I have no idea whether that will reach anyone who can resolve the problem. I also submitted a report to Apple by FBA and included a video of what happens when the app is launched but I don’t believe this is related to ios.