Duplicity & S3: "The write operation timed out"

Question

I'm trying to set up an automated backup with duplicity on Amazon S3, but I keep getting a weird error that doesn't show up on Google searches.

machina:~# duplicity --version
duplicity 0.6.14

Here is the script I'm using:

#!/bin/bash

export AWS_ACCESS_KEY_ID=????
export AWS_SECRET_ACCESS_KEY=????
export PASSPHRASE=????

duplicity --encrypt-key=A36FFD9E --sign-key DA5D5B8B --s3-european-buckets --s3-use-new-style /source/folder/ s3+http://[bucket].s3.amazonaws.com

export AWS_ACCESS_KEY_ID=
export AWS_SECRET_ACCESS_KEY=
export PASSPHRASE=

...and the output:

machina:~# ./backup.sh 
Local and Remote metadata are synchronized, no sync needed.
Last full backup date: none
No signatures found, switching to full backup.
Upload 's3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg' failed (attempt #1, reason: SSLError: The write operation timed out)
Upload 's3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg' failed (attempt #2, reason: SSLError: The write operation timed out)
Upload 's3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg' failed (attempt #3, reason: SSLError: The write operation timed out)
Upload 's3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg' failed (attempt #4, reason: SSLError: The write operation timed out)
Upload 's3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg' failed (attempt #5, reason: SSLError: The write operation timed out)
Giving up trying to upload s3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg after 5 attempts
BackendException: Error uploading s3+http://[bucket].s3.amazonaws.com/duplicity-full.20110910T164251Z.vol1.difftar.gpg

I've tried running the script multiple times, to no avail. Has anyone already encountered this?