Error messages

Dear all,

we have constant error messages on the admin page of our websites https://www.monteofelio.com and https://www.monteofeliobar.com – it’s not possible to “review page” or “publish page” without the whole site crashing down and after that, I have to login again. Has anyone an idea how I can quickly fix the issue and get rid of all the error messages? It’s really annoying that the site is constantly crashing down and also, when I am trying to adapt something on a site, it takes ages to open the window within the admin page (e. g. changing text elements). Thank you so much!

Best,
Kerstin

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