White screen on new or editing posts

I am having problems with my site. When I attempt to edit an old post/page or add a new one I get a completely blank white page – sometimes. There is no rhyme or reason to it. Yesterday it worked today it won’t work at all. Some days it will work on my PC but not on my Mac. It’s driving me nuts. I can reach my dashboard and see all my posts but it will not let me work on anything.

I am not a technical person and I don’t understand about editing code or whatever. All I know is it doesn’t work how it is supposed to and I’m not doing anything different. I thought it was the Gutenberg editor but as I say some days it will work. I don’t know what to do.

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