Ubuntu rsync to synology: IP denied

I am trying to sync my (new) Ubuntu webserver directory to my Synology NAS.

Network backup is enabled, when I do a dry run:

rsync --dry-run . rsync://root@192.168.1.150

It shows the available modules.

When I try to sync with rsync it fails with the message:

@ERROR: host is denied to login

Syncing is done with this script:

#!/bin/bash
RSYNC="/usr/bin/rsync -a --delete"
export RSYNC_PASSWORD=MyPasswrd
rsync -avz -t --timeout=1200 /var/www/ root@192.168.1.150::NetBackup/web/var/www/

All directories are tested. This worked on my previous Ubuntu server (10.04)

/var/log/rsyncd.log:

2013/12/31 02:22:58 [8601] rsyncd version 3.0.9 starting, listening on port 873
2013/12/31 02:23:05 [10188] name lookup failed for 192.168.1.51: Name or service not known
2013/12/31 02:23:05 [10188] connect from UNKNOWN (192.168.1.51)
2013/12/31 02:23:05 [10188] module-list request from UNKNOWN (192.168.1.51)
2013/12/31 02:23:19 [11408] name lookup failed for 192.168.1.51: Name or service not known
2013/12/31 02:23:19 [11408] connect from UNKNOWN (192.168.1.51)
2013/12/31 02:23:19 [11408] rsync error: IP is denied by remote machine (code 50) at authenticate.c(563) [Receiver=3.0.9]

UPDATE

My database server, same Ubuntu version, installed as a second server together with my webserver is using the same script:

#backup the tables to NAS
RSYNC="/usr/bin/rsync -a --delete"
export RSYNC_PASSWORD=MyPasswrd
rsync -avz -t  --timeout=1200 /home/user/backup/mysql/ root@192.168.1.150::NetBackup/mysqldb/

And this works flawlessly…

UPDATE 2*

with verbose (-v)

opening tcp connection to 192.168.1.150 port 873
sending daemon args: --server -vvlogDtprze.iLsf --timeout=1200 . NetBackup/webserver/var/www/
@ERROR: host is denied to login
rsync error: error starting client-server protocol (code 5) at main.c(1534) [sender=3.0.9]