Trouble with Spanish charset encoding

I’m using the UTF-8 charset encoding for my site in WP. Apparently everything works fine, since in the website the characters appear correctly. But when having a look at my site at https://www.seo-browser.com/ I get this funny characters. I’ve been looking through other websites with the same encoding, but they get they characters displayed correctly. Can you tell where’s the problem? My website is https://www.creativasfera.com
Thanks for your help, any tip will be highly appreciated!
Sandra