When you deploy a Teradata ecosystem from a solution template, you can use the NTP server list parameter to change these to your own public or private time servers. You must open the appropriate inbound UDP ports in the Network Security Group for NTP.
When you deploy a single VM from an image, you are typically adding VMs to an existing Teradata ecosystem so the NTP must be configured manually to match that of the existing ecosystem. Contact Teradata Consulting Services for assistance. See https://www.teradata.com/Consulting/Velocity.