Winswcp just won't work correctly

Alright, so I'm trying to get winscp to conect to my iPhone. It's been working amazingly the past week or two, but lately it has been going EXTREMELY slow, and when I have to patience to wait for it, it won't transfer any files. I tried it on a different computer and it worked fine, so it's got to be someting with the computer. Des anyone know a fix?