lftp stuck at `ls' at 0 [Connecting...]

I'm running lftp on a centos 7 machine and trying to upload files to my hosting account at ftpupload.net. I can log on ok but when I run ls I always get `ls' at 0 [Connecting...] and it just hangs.
I've been trawling google but there's no definitive answer I can find that works and I've tried switching ssl off but it still doesn't work. I've also asked for help at the hosting forum but I don't think they understand lftp very well. I can get a connection with filezilla on a desktop pc but I'd brefer to use lftp - if I can ever get it to work. thanks for any help.