Failed to save modifications to the server when importing data from xlsx format

I was using Power BI Desktop to get data from an old .xlsx file and was thrown following error "Failed to save modifications to the server. Error returned: 'OLE DB or ODBC error:[ DataFormat.Error] Invalid cell value '#Value!'..'.  The weirdest thing about it was working ok until I added a 'Unpivot other columns' step?!

Can someone help me to find out what this error is about?