Here is the end of the log.
04-13 22:40:16.907 20168 20168 D Notification: allPendingIntents
04-13 22:40:16.908 20168 20168 V PushService: PushService.onDestroy()
04-13 22:40:16.910 20168 20168 D AndroidRuntime: Shutting down VM
--------- beginning of crash
04-13 22:40:16.910 20168 20168 E AndroidRuntime: FATAL EXCEPTION: main
04-13 22:40:16.910 20168 20168 E AndroidRuntime: Process: com.fsck.k9, PID: 20168
04-13 22:40:16.910 20168 20168 E AndroidRuntime: android.app.RemoteServiceException: Context.startForegroundService() did not then call Service.startForeground()
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1881)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:105)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at android.os.Looper.loop(Looper.java:164)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:6944)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
04-13 22:40:16.910 20168 20168 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
Unfortunately it does not look very helpful.