Gutenberg Paragaph block wont allow me to change font size

Hello all,

I am experiencing errors when trying to edit/post articles. Initially the “add post” function worked well, until I tried to delete a reusable block on the article I was writing. When I did so, the page froze and won’t do anything. I was force to close page and reopen the draft. When I did so, I could no longer change the font sizes on the paragraph block. Anyone who can help me with this?

This same issue happened with my other website and it caused major problems which I haven’t been able to resolve till now. Hope you can offer some assistance.

Thanks!

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