426 failure writing network stream

So, I enabled FTP on MBLD. Within home network, everything works fine. However, whenever someone from the internet tries to download files (small files under 15mb seem to be unaffected by this issue, they transfer no problem), they are met with the following error…

426 failure writing network stream

To be specific, a particular file will freeze at the same spot every single time. For example, a 50mb file freezes at the 11.4mb mark while transferring, and a 60mb file freezes at 53.6mb mark while transferring.

Any ideas on what the problem could be? Thanks in advance.

Be sure to have the latest firmware update, if you already have, check the link below to review the steps to enable FTP, you can also try pressing the reset button on the back of the my book for 4 seconds.