I ran into the the same problem with my Denon receiver when I bought my first 4k tv. Was never able to resolve the problem. I was told it might be my older Denon was unable to processs the 4k signal or something like that. It's kind of annoying not being able to bring the menu up on screen.
This usually has to do with video processing. If it is not enabled then the receiver is essentially a pass through device and so cannot overlay graphics onto your screen. Look through your menus for something similar to "Video Conversion or "Video Scaling" and make sure the setting is enabled.
Did you recently move or disconnect/reconnect the receiver?
I have either that model or one very similar and it has two HDMI outputs in the back, but only one of those two is capable of displaying an onscreen menu. Any chance the cable from the receiver to the TV got switched to the output that doesn’t output the onscreen display?