It's possible for the VM clock drift sometimes. The easiest way to reset the clock is to use an online time server.
Log into the VM and execute the following command:
ntpdate -s time.nist.gov
Viewing Details:
-bash: ntpdate: command not found
I'm running MindTouch Core 9.02.2 (VM package).
You may install "ntpdate" command by root user as:
# apt-get update
# apt-get install ntpdate
Hope this helps.
Also discovered that I had to enable internet-bound traffic with the following command:
# route add default gw 192.168.10.1
...where 192.168.10.1 is my Internet gateway/router. Then the apt-get commands were successful, and finally, so was the ntpdate command.