• Synchronize date and time between the physical machine and the VMs running on your system:

  # apt-get update
  # apt-get install ntp

• Check whether the correct date and time, and the connection to a time server, has been established:

  # date
  # ntpq -p

• If you run ntpq -p and you get

  No association ID's returned

• Run

  # dpkg-reconfigure ntp

• And then again

  # ntpq -p

# dpkg-reconfigure tzdata

You need to restart the apache2 service for php to recognize the changed timezone.

• Debian NTP