Don't know if this will be of any help... (nothing to loose) but the same was happening to me... And the solution has nothing to do with Xara or any FTP client...

I could not read nor upload anything to one my hosting companies... Bluehost. But could read the site with my phone data. (Wifi turned off) Called them many times
was getting nowhere until one agent kinda laughed and said NONE... of what any of the other agents told me was right and the problem was coming from my ISP...
which by the way is COMCAST.

He said they have a 'security' feature that's preventing me from accessing my host. The fact that I could read it with my phone data proves it not "us".
"Call the and tell them exactly that and stand firm. Don't let them push it back to us."

Sure enough... Two Comcast agents did exactly what he said they would do.... "push it back to them." I insisted on a manager and got a gal who said "yes, he was
correct." She showed me where in my Comcast settings I could disable the security feature and BAM! Done!

So who knows? Maybe it's you ISP??? Hope you get this resolved...

Cliff

PS.... I still get an occasional time-out... but rarely. And if it won't fix.. I just reboot Xara and all good.