Hello!
I checked out Topic "winscp disconnects every few seconds and does not reconnect" but I could not solve the similar issue.
I start a transfer which work 2 or 5 seconds then brokes and I have to reconnect to continue it. After 1-5 seconds it brokes again. And again...
I tried to set the mentioned keeplaives and of course increased the time-out period but the problem still exists.
Any useful help?