Thanks for the details. Are you using the latest version of Chrome?
Microsoft supports Excel for the Web in Chrome when it is fully updated. The "Content is Blocked" message usually happens because of how Chrome handles popups and cross-site content. Make sure Chrome is updated (Chrome menu > Help > About Google Chrome), check that no security or antivirus settings are blocking content, and confirm you are signed into your Microsoft account in the same browser profile. If it still does not work, I recommend using Edge, which is fully supported for Excel on the Web.