Tried to change http to https. Now the site is listed as unsafe and does not open. How to return http back?

Question

Communication protocols

I read an article on how to change http to https ( I'm a "teapot" :( ) , tried to change the hhtp address in the Administrator panel (settings, general), added the letter s, as advised. I pressed save. I received information that the site is "unsafe and the entrance to it is closed, contact the owner. Now the site does not open through the search engine, they write - an insecure connection. If you try to access the pages of the site from old links, it gives out - "Sorry, there's nothing here, contact the owner.
Huge request, help return everything back!!!Please!

Answer 1

Well, you still need to buy a certificate, and not just add "s".