When I click the 'Customise' menu in 'Appearances' tab I get the following error:
The site is experiencing technical difficulties. Please check your site admin email inbox for instructions."
I have entered my mail chimp key and it is still not working.
**I am trying to change the footer details like the address and am unable to find it.
Do you use any strange plugin that theme does not required. It might caused a conflict code with our plugins.
This topic will show you more details of the problem and the way to fix it:
How to Fix the WordPress Error “The site is experiencing technical difficulties” - WP Fix It