thuyltt thank you so much for your help. I am very sorry I didn't reply before it's just I figured out what the problem is.

The fonts that I don't see working correctly are those that are requested to Google Fonts. By default, SJ Plus has Titilium Web selected. I chose "none" like you recommended me. The problem is that there are explorers like Chrome, Opera, Edge, that block these fonts from being seen. They disable scripts that they consider unsafe. If I unblock this feature, it shows that the problem is "Mixed Content: The page at 'escueladecristointernacional.com/' was loaded over HTTPS, but requested an insecure stylesheet 'fonts.googleapis.com/css?family=Montserrat'. This content should also be served over HTTPS."

So for now I leave the Google Fonts at "none". If you can help me how can I load a Google font without this request being "insecure", I will appreciate it. Thank you very much.