Not running the report, just trying to click 'save' after uploading an XLS template to use. I am able to run the report ok. However, since I am unable to actually save it with the file uploaded you probably wont be able to see the template file in the account. I can email it to you if you would like?
Here is the template - https://varro.jsreportonline.net/studio/xlsxTemplates/BO6iY9G