Cant download Exported file

Hi, I’m using Plugin Version 6.4 (licensed). I’m trying to export a custom post type. It runs through the whole process and a download button is displayed, but then why I click the download button, the download doesn’t come though. The message from the browser is “Failed – No File”. The plugin reports that there are 156 records to export.

This is in both Chrome & Firefox. Both for CSV and XLS.

Is this a write permissions issue on the server? Which directory needs to have which permissions?

Thanks for your help!