Deploying keeps waiting on uploading file

I am using qtcreator 3.5.1, based on qt5.5.1, target: TI's arm, with arago filesystem (andd added ssh, sftp-server)
I cross compiled, and try to debug a remote device.
But than it keeps waiting as following:

15:33:33: Running steps for project testapp...
15:33:33: Configuration unchanged, skipping qmake step.
15:33:33: Starting: "/usr/bin/make"
make: Nothing to be done for `first'.
15:33:33: The process "/usr/bin/make" exited normally.
15:33:33: The remote file system has 2560 megabytes of free space, going ahead.
15:33:33: Deploy step finished.
15:33:33: Uploading file "/home/user/build-testapp-GSDU-Debug/testapp"...

And nothing happens from here any more (no timeout, no printing, just keeps waiting) , sort of hang (but I can stop the process by clocking the stop button)
there is also a deploy status bar in the right botton on screen which says "finished 3 of 4 steps"

1. I've validated that ssh, sftp , gdb - all works OK (without qt)
2. I've also tried just to deploy (without debug), but it also keeps waiting.
3. If I remove the sftp step in the "run" configuration for the kit, than it continues to run application and finishes ok.
4. I've also tried the "test" device in qt, and it all works completely from inside qt: including the key deplyment.

Any idea how to overcome this ? Is it related to openssh/sftp-server/dropbear in target ?