SharePoint online excel editing

hi all, 

I have challenges with Editing an excel file on the browser, when opened in the browser it opens in read-only mode.  when opened in-app it gives a warning message "Some files can contain viruses or otherwise be harmful to your computer. It is important to be certain that this file is from a trustworthy source.

Do you want to open this file?"

kindly see attached screenshots and advise.