Admob shows off and on. sometimes it shows and sometimes it doesnot

@nite Hello, i am using, admob sdkbox. I use reward videos and banner ads. So my app is in the play store ‘What Yuh Know’ you can check it out to see what im talking about. The banner ads show and after return a few times to the game it don’t show. Same goes for the reward video. Is there a reason for this? Thanks in advance