Hello,
The method createDocxAndDownload included in phpdocx uses generic headers to download the files. It these headers don't work on your server, we recommend you to check if your server is returning the right content type for DOCX files or use the method createDocx with custom headers or the function ob_start from PHP.
As you are using the trial package, after you have bought a license, please write to contact[at]phpdocx.com and the dev team will help you.
Regards.