Hi. I am using Samsung Galaxy S4 LTE-A i9506 running on Android 5.0.1 and after I installed f.lux on my device, I open the app and it crashes and shows a black screen. I pressed the power button to lock my device and afterwards unlock my device back. I reopened f.lux and it is able to be opened but it is not working. The colour of my screen is still the same. However, I tried to install f.lux on my brother's phone: Samsung Galaxy S4 LTE i9505 running on Android 5.0.1, it works perfectly. No bugs or blank screen after installing the app and its functions work. That is what I'm confused about. Please fix this. Thanks.