Hi JoeGuestSr,
Based on your description, after publishing the Excel workbook to html file, it won't open the workbook from the browser.
You can try to switch to other browsers to open the html file. And may I confirm that whether the problem happen on all the Excel files?
Additionally, I found a thread which has the similar problem with you: Converting HTML to Excel?. You can try the VBA code in this thread to check whether it could help you.
Additionally, please provide a screenshot of your Office Product Information(open Excel>File>Account>capture a screenshot of the Product Information column).
Best regards,
Jazlyn