FTP uploads started to appear with zero length

I had not done any uploads in a while. Now my ftp uploads are getting aborted, so it seems:

ftp> put especialista_Gabriela_Reza.php local: especialista_Gabriela_Reza.php remote: especialista_Gabriela_Reza.php 229 Entering Extended Passive Mode (|||25962|) 150 Opening BINARY mode data connection for especialista_Gabriela_Reza.php 100% |***********************************************************************************************| 5606 74.25 MiB/s 00:00 ETA 450 Transfer aborted. Link to file server lost 5606 bytes sent in 00:43 (0.12 KiB/s)

I tried Cyberduck also to no avail. Any ideas?