What's wrong with ssl?

Question

Digital certificates

Got a free certificate for wosign. Installed on the site. The laptop is working, the green one is as it should be. And from Android Chrome, a warning came out and https is red and crossed out. What to fix? Website here: https://randomfio.xyz/

Answer 1

It looks like the web server, in addition to the certificate, also needs to be given a chain of certificates with which they signed. They don't send anything like that?