Can’t change theme | WordPress.org

I have been trying to change the theme of my website without success and I don’t know how to fix it.
I go appearance tab and click blocksy and picked the pre-built page and hit activate but it will not change on my website even tho on wordpress it says it’s active. I tried clearing cache on browser and wordpress and nothing seem to work. It’s just the default twenty twenty theme. Tried updating php version, logging out relogging , open website as incognito but nothing works. Any ideas?