Previously pressing the Excel toolbar item would present the report as an Excel spreadsheet in the web browser or download it so it could be opened in Excel. The type of behaviour depends upon the browser and operating system.
You may receive other messages like "The file is corrupt and cannot be opened"
Recent Microsoft Security Updates are blocking Excel downloads from websites unless they are trusted. The BI4Cloud is a Cloud application and treated as a website
To fix this on your web browser you need to trust the BI4Cloud URL's
These are *.bi4cloud.com and *.biforcloud.com
There are far too many variations of web browser types and version for us to document each of these so Google is your friend :-)
You need to Google for instructions on how to set the Trust in your web browser.
Try typing "Trust website in <insert the browser you use>"
eg Typing "Trust websites in Chrome" returns the page below.