Initially you had an issue with your base being a sheet with no thickness. It looks like you understood the problem and fixed it by adding a base. Take note that if you want to simulate the wind flow around the landscape topography you need a mesh of the air volume around the landscape, not the landscape itself. To do this, go to geometries, click on the drop down menu on the right of your geometry and under ‘add geometry operation’, choose enclosure. This enables you to form a mesh of the air around the landscape. There are several tutorials on the website which include use of the enclosure function, I’ve linked one of them below.
Now for the bad news; your geometry is extremely complicated because of all the tiny features with small radii and so you lack the RAM to even mesh this geometry. You can get more RAM by choosing a higher number of processors but unless you are a professional user, 16 is the maximum. To be honest, I am not even sure if the full 96 cores would be enough for this truly complex geometry. You would have to greatly simply your model, ironing out all of the small features, to have a chance of solving it.