Downloads stops right before completion

Program: NZB-o-Matic
Server: Giganews

This program has worked forever for me, but suddenly one or two downloads has started stopping right before completion, like: 400/401 or 89/90 which keeps them from being created in the folder - so I can't do a repair through quickpar either. There's probably other programs, but I'd rather have a solution to this one as I have to download 30-40gb of that NZB again if I choose a new program.

If NZB-o-Matic has an option to decode partial files and that option must be set, then do so. Don't use an old version of NZB-o-Matic which doesn't handle decoding of partial files. Don't let antivirus or firewall interfere with NZB-o-Matic downloads.