How to go through this duplicity stalled connection?

I am trying to set up backups via duplicity.

Here is the use case:

~$ duplicity --encrypt-key CA17A4FA --progress --ssh-options="-l 8192" ~/Documents/ ssh://my.distant.host/save/docs/Documents
Local and Remote metadata are synchronized, no sync needed.
Last full backup left a partial set, restarting.
Last full backup date: Sat Sep 20 12:00:49 2014
RESTART: Volumes 14 to 14 failed to upload before termination.
     Restarting backup at volume 14.
Restarting after volume 13, file je/transfère/un/fichier, block 82
0.0KB 00:00:00 [0.0KB/s] [>                                        ] 0% ETA 0sec
0.0KB 00:00:03 [0.0KB/s] [>                                        ] 0% ETA 3sec
0.0KB 00:00:06 [0.0KB/s] [>                                        ] 0% ETA 6sec
0.0KB 00:00:09 [0.0B/s] [>                                        ] 0% ETA Stalled!
0.0KB 00:00:12 [0.0B/s] [>                                        ] 0% ETA Stalled!
0.0KB 00:00:15 [0.0B/s] [>                                        ] 0% ETA Stalled!
0.0KB 00:00:18 [0.0B/s] [>                                        ] 0% ETA Stalled!

I've tried the MTU trick (e.g. ifconfig eth0 mtu 576 on both hosts).

I have two servers, one is mine and the other is OVH's. For both it doesn't work.

On the machine from which I am trying to backup there is a debian wheezy box, and I have installed the wheezy-backports' duplicity version.

Thank you by advance.

It may be a bug in Duplicity: https://bugs.launchpad.net/duplicity/+bug/1482841

In brief, the progress bar is not being updated. (--verbosity debug confirms the process is working, but --progress does not change.)