Error after adding mobile broadband connection to network manager

[MichiGreat]

I am running Ubuntu MATE 16.04 x64 Alpha 2. In network manager, I added a new mobile broadband connection ("Bob" in "Austria") after successfully unlocking the SIM card of the modem using modem-manager. After the last step in the wizard an error message is being displayed:

Adding/activation of connection failed

(1) Creating object for path '/org/freedesktop/NetworkManager/ActiveConnection/2' failed in libnm-glib.

The entry "Bob Vorgabe" (should be "Bob default" in English, I guess) shows up in the network list in network manager, but when I click the entry, network manager just shows the "connecting" icon for a fraction of a second and then does nothing. syslog is enhanced with these lines:

Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): Activation: starting connection 'Bob Vorgabe' (1a46eedf-d89d-47a2-b9bc-28518aca893e)
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): device state change: prepare -> need-auth (reason 'none') [40 60 0]
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): device state change: need-auth -> prepare (reason 'none') [60 40 0]
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <warn> (ttyUSB1): Failed to connect 'Bob Vorgabe': Connection requested both IPv4 and IPv6 but dual-stack addressing is unsupported by the modem.
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): device state change: prepare -> failed (reason 'modem-init-failed') [40 120 28]
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> Disabling autoconnect for connection 'Bob Vorgabe'.
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <warn> (ttyUSB1): Activation: failed for connection 'Bob Vorgabe'
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> (ttyUSB1): device state change: failed -> disconnected (reason 'none') [120 30 0]
Feb 8 07:40:16 TravelMateB115M NetworkManager[658]: <info> Device 'ttyUSB1' has no connection; scheduling activate_check in 5 seconds.

In Xubuntu 12.10 and 14.04 I never experienced such issue.

My guess is that line #5 causes the problem, but I have no clue how to tell it to only try IPv4.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: network-manager 1.0.4-0ubuntu9
ProcVersionSignature: Ubuntu 4.4.0-2.16-generic 4.4.0
Uname: Linux 4.4.0-2-generic x86_64
ApportVersion: 2.19.4-0ubuntu2
Architecture: amd64
CurrentDesktop: MATE
Date: Mon Feb 8 07:30:49 2016
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2016-02-06 (1 days ago)
InstallationMedia: Ubuntu-MATE 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160127.1)
IpRoute:
 default via 192.168.43.1 dev wlp2s0 proto static metric 600
 10.0.3.0/24 dev lxcbr0 proto kernel scope link src 10.0.3.1
 169.254.0.0/16 dev wlp2s0 scope link metric 1000
 192.168.43.0/24 dev wlp2s0 proto kernel scope link src 192.168.43.142 metric 600
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'.