GanttProject will not display an imported xml file

Hi folks, I’ve exported a XML & a CSV file from ‘ProjectManager.com’ and tried to import them into GanttProject but the screen displayed but GanttProject is blank. Am I missing something here? Any help would be appreciated. Thanks, Chris.

Can you attach a sample of XML file?

No, it won’t allow uploading XML files?

I just have enabled XML extension in the files upload.