Visits Overview gadget is throwing error

In my Matomo installation, dashboard view is throwing following error. Please help me understand how to resolve it to view the data. Thanks in advance.

Oops… there was a problem during the request. Maybe the server had a temporary issue, or maybe you requested a report with too much data. Please try again. If this error occurs repeatedly please

Hi,

This just means that there didn’t come any valid response from the server.
So to find out what’s wrong, one question?
Did the error pop up really soon after loading the page? Then it is very likely that some PHP error is occuring on the server. To find out which one exactly, you need to check the PHP error logs.

Or did the page load for a long time and then show this error? In that case it is more likely that the request simply took a very long time and got aborted by the PHP maximum execution time.