Plugin has become inaccessible and other errors

With the new update I am no longer able to access the plugin settings from the WP backend.
When the plugin is active in the WordPress backend you can see the html codes (see photo: html) and in the frontend (all the pages and articles of the blog) the accent letters are not visible (see photo: lettere accentate).
Can you solve the problem?
Thanks for everything.

• This topic was modified 3 years ago by chicercatrova.