The given key does not identify an element in this collection value- OCI

Hi I am trying to deploy a new network environment and I keep getting the error below. I have no idea what this means (new to terraform) so any help interpreting would be so appreciated.

<code>
Error: Invalid index

  on .terraform/modules/network/main-region1.tf line 51, in resource "oci_core_drg" "drg_pri":
  51:   compartment_id = oci_core_virtual_network.vcn["reg_hub_vcn_pri"].compartment_id
    |----------------
    | oci_core_virtual_network.vcn is object with 4 attributes

The given key does not identify an element in this collection value.


Error: Invalid index

  on .terraform/modules/network/main-region2.tf line 51, in resource "oci_core_drg" "drg_sec":
  51:   compartment_id = oci_core_virtual_network.vcn_sec["reg_hub_vcn_sec"].compartment_id
    |----------------
    | oci_core_virtual_network.vcn_sec is object with 4 attributes

The given key does not identify an element in this collection value.
<code>