The screen goes black when i enable/disable f.lux

[InvalidUsername]

When i grant it root permission for the first time, the screen goes black. I turn off and on the screen and it works again. Disable/enable f.lux cause black screen again.

Here is the logcat file. Ignore the gokeyboard errors
http://usersdownload.com/3p0jmjwb62vm.html

My device is Sony Xperia Z3 Compact running Android 5.1.1. SuperSU 2.78