When the file passed to the static method PHPEXCEL_IOFactory :: load is a file with a temporary extension (* .tmp), the createReaderForFile method determines that it is an HTML file, then causing an error when using Of the DOM since it is not necessarily an html file.
To be more precise, if the temporary file is based on a file of type xls, odt, ... it works but if the tmp file is for example PNG type, it will consider it as an html file then
When the file passed to the static method PHPEXCEL_IOFactory :: load is a file with a temporary extension (* .tmp), the createReaderForFile method determines that it is an HTML file, then causing an error when using Of the DOM since it is not necessarily an html file.