During the creation of the material for the landscape, one part stopped loading.When you try to draw, textures from other areas disappear
You’ve probably run out of texture space.
Just click on all your textures and, in the details, change sampler source from ‘texture asset’ to ‘shared: wrap’
I didn’t understand where and which textures to click on 
Thanks a lot for helping!
you really helped me, thank you!!!
