The site is experiencing technical difficulties

For the last two weeks have experienced this error when trying to do blog posts:

“The site is experiencing technical difficulties. Please check your site admin email inbox for instructions.”

No email received. The rest of the site is running fine.

Only changes I can think off made on the site is a new plugin for google reviews and an updated SSL certificate from GoDaddy in June.

No idea how to start troubleshooting – i have seen other similar threads but none fit the same issue as me, hopefully someone can help, thanks

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