I can’t import the church demo or any other demo. I was asked to download and activate the events calendar plugin before I could import the church demo but this is error message I get when I try to activate the theme ”

I have a similar problem. I tried importing the church demo but was asked to download and activate the events calender plugin. I was successful in installing it but whenever I try to activate it, I get this
”Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.” Please help fix it.”