Landscape won't edit

Hi there,

I am having troubles with landscape editor. I am new to Unreal and following online tutorials. I have just placed a green grid as a new landscape and imported some floor materials from the library source. I am trying to sculpt mountains but the sculpt and brush tool won’t make any modifications on the landscape when I click.

Thanks for your help in advance,

best,
M

Are you seeing the purple circle?: