My landscape disappears when I press play

The blueprint of the landscape material has the default settings.
Does anyone has a solution for this?

287093-actorhiddeningame.png

Is it in persistent level? Can you see it in actors list in right side of Unreal (by default) while playing?

Thank you for the response.
It is in the actors list while playing, but it’s not marked yellow.

Here for better understanding:

287251-screenshot-6.png