Unable to create directory wp-content/uploads

I am trying to build a website (old one still active) with wordpress (in Google Chrome), but when I want to upload images I get the error “Unable to create directory wp-content/uploads. Is its parent directory writable by the server?”.

I have already changed the file permissions to 666 of the index.php in the root file as well as in the wp-content, themes and sixteen-plus file, but this doesn’t help (I’ve done this using Filezilla)

What can I do to get this working? Otherwise, I cannot build my website.

Thanks for the help!