QR RuntimeException: Fail to connect to camera service

Today, for the first time, I am unable to add contacts with two devices. One device just doesn't want to focus on the QR code. I am still trying to get it to work (because I need to test something else) and then managed to crash Briar:

04-06 17:48:10.855 W/ShowQrCodeFragment: Error opening camera
                                         java.lang.RuntimeException: Fail to connect to camera service
                                             at android.hardware.Camera.native_setup(Native Method)
                                             at android.hardware.Camera.<init>(Camera.java:323)
                                             at android.hardware.Camera.open(Camera.java:298)
                                             at org.briarproject.android.keyagreement.ShowQrCodeFragment$3.doInBackground(ShowQrCodeFragment.java:212)
                                             at org.briarproject.android.keyagreement.ShowQrCodeFragment$3.doInBackground(ShowQrCodeFragment.java:196)
                                             at android.os.AsyncTask$2.call(AsyncTask.java:287)
                                             at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
                                             at java.util.concurrent.FutureTask.run(FutureTask.java:137)
                                             at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
                                             at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
                                             at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
                                             at java.lang.Thread.run(Thread.java:856)

IMHO this error should be handled more graceful.