PPTP VPN is Blocked by Sohos UTM firewall

I have a functioning Sophos UTM firewall setup with the exception of not being able to successfully use the built-in windows VPN and a commercial VPN service. When I replace this firewall wall with my previous older firewall the VPN service successfully connects to the remote site. So it has the be a policy on the Sophos UTM Firewall.

The error messages are:
Windows7 VPN: Times out at Verifying User Name And Password
Windows8 VPN: Error 628 the connection was terminated ...
The Commercial VPN service:
2/17/2014 2:29:38 PM  Connecting...
2/17/2014 2:29:38 PM  PPTP connection state changed to OpenPort; status: ok
2/17/2014 2:29:38 PM  PPTP connection state changed to PortOpened; status: ok
2/17/2014 2:29:38 PM  PPTP connection state changed to ConnectDevice; status: ok
2/17/2014 2:29:38 PM  PPTP connection state changed to DeviceConnected; status: ok
2/17/2014 2:29:38 PM  PPTP connection state changed to AllDevicesConnected; status: ok
2/17/2014 2:29:38 PM  PPTP connection state changed to Authenticate; status: ok
2/17/2014 2:29:40 PM  PPTP connection state changed to AuthNotify; status: ok
2/17/2014 2:29:59 PM  PPTP connection state changed to Disconnected; status: The connection was terminated by the remote computer before it could be completed.
2/17/2014 2:29:59 PM  PPTP client dial completed: DotRas.RasDialException: The connection was terminated by the remote computer before it could be completed.
2/17/2014 2:29:59 PM  Failed to establish PPTP Connection.

Here's what the firewall itself reports: 15:28:14 Packet filter rule #1 TCP       192.168.XX.XXX:58747 ¿ 173.220.213.101:1723 [SYN] len=52 ttl=127 tos=0x00       srcmac=0:1c:c0:ac:f5:cc       dstmac=0:c:29:fa:15:67

Checked the following logs:
Application Control - not triggered
Intrusion Prevention - not triggered
Web Application Firewall - not triggered
Web Filtering - not triggered

I have been trying all possible changes I can think of, to no avail.
Can you help?
Johannes Banck