Suddenly Safari stopped downloading excel files

Working with Microsoft Forms using Safari browser on MAC High Sierra. On the Forms website page there is an option to in Excel. Normally it would download the relevant Excel file for viewing by Numbers are Microsoft Excel for MAC. My issue is that this worked fine some weeks ago but has suddenly stopped working with a message "Safari can't open this page". On Google Chrome it works fine. I would rather stay with Safari.

Any ideas would be helpful. I have checked in Safari Preferences, websites, downloads etc and all seems fine. I have made no changes.

Thanks for any advice, Douglas.