Please tell me what to do with this error, could not find a solution on the Internet
It means you need to set the intensity of your contact shadows in the details pane on your light, not via a CVar. Does your scene have any artifacts as a result of the shadowing?
Same problem, how to solve?
In the console text field, bottom left, type in :
r.ContactShadows
At this stage Unreal will suggest you the entire command with NonShadowCastingIntensity
Select it then hit space and type in 0 (zero)
Hit enter, message gone.
This command line with 0 value disables the command variable r.ContactShadows etc etc that is deprecated.