File Uploading and Attachment don't work

File Uploading and Attachment works flawlessly for me on several sites. Any problem your are having is most likely due to your particular WP and server configuration.

Perhaps, but after several hours of hard work, I installed another similar plugin that worked right away.
Therefore, I suspect CF7 having a problem with some configurations. Must be corrected as soon as possible.

Rocou, FYI it is very difficult to debug a problem like yours without more detailed information. “It doesn’t work” is never enough to go on so correcting it (assuming it actually is a problem with CF7 and not the server or other configuration setting) isn’t likely to be forthcoming. Maybe you can tuck that away for future reference.