Sleep/wake button unresponsive for a few minutes and then it works again

Once a day or so the sleep/wake button on my iPad Pro 9,7 wifi+cellular becomes unresponsive. I can use the home button and the touch do also still work, but I am not able to turn off the screen because the button doesn't react when I am pressing it. I am thinking it might be a software problem but I don't know... Anyone who have a solution?