Asterisk virtual machine stops responding to network connections when I connect with Phoner Lite

I've installed Asterisk Now with PreePBX from bootable CD to a VirtualBox machine.

Then I updated through FreePBX all the modules available for update and noticed a strange behaviour:

After I attempt to connect to Asterisk with PhonerLite client the virtual machine stops responding to TCP/UDP connections. I can't access it through SSH console, FreePBX does not respond through network.

I can log on locally, start lynx and enter FreePBX in text mode. Also I can only log in locally and reboot the machine. After that everything is ok until I attempt to connect to Asterisk.

There is no dependence on Virtualbox networking mode.