usb debugging – The Developer Options screen opens for one second, then closes

I'm using an LG4c Android v5.0.2. I've enabled options for developers – it's in the menu where I can tap on to open it.
When I touch it, it opens for a split second – enough to see that it is activated (the blue button is activated) and turns off almost instantly, so that I can not to access.
How can I get it to stay on? Why does not it stay?