titles disappeared

Hello!

All the titles of individual posts disappeared. They show in the homepage, but not in the individual posts. The link above is an example only.

I’m not sure if it has to do with the update to wordpress 5.5 because I was away from the site for some days prior to the update.
I did have problems with the customizer, installed the plugin Enable jQuery Migrate Helper and it looks ok. But the titles didn’t came back!

I believe that just now you are focused on the bigger problem, but I hope you can find a moment to suggest what I can do!

best regards!

The page I need help with: [log in to see the link]