How can I delete these folders?

System Issues
1

How can I delete these folders? Prompt me that I don’t have permission to delete.
Sorry, because I am a newcomer and I don’t know how to delete it!

2

When I was testing whether I could create subdomains, I created them as first-level domains. Does this cause me to have no right to delete these folders?

3

@FuChengK
Rename them to ‘unused’ or something.
They can’t be deleted.