Two-button screenshot facility not working

[DG16052020]

I have a Samsung Galaxy A7 and an A7 Lite. Until recently I've always been able to take a screenshot by pressing the power and volume buttons together (I could do this with my Google Nexus 7 too). Now this doesn't work. Any idea why?

 

[mustang7757]

Usually it's the power and volume down to take a screenshot, did you remap the power button to none or something else?