Update fails with "Check internet and try again"

If when you attempt to install an update of the A2 software on your appliance and the update fails, it may produce output like below:

If you receive this output, it means one of two things:

1. Your A2 is behind a firewall or cannot reach Ubuntu update servers. Please open outgoing traffic restrictions to enable the A2 to contact the Internet temporarily.
2. Your A2 has minor Ubuntu package database corruption. These Ubuntu databases can rarely become damaged through routine operations. In such cases, the best intervention is to simply download a new A2 image, update it, shut down the old A2, reconnect ADS/ODS, and re-license. You can reset the activation of your keys at portal.quadricsoftware.com. Be sure to re-apply the keys and re-license your hosts on under the hosts page.