Error: Invalid value for module argument when running terraform plan

Terraform
1

I am trying to run Terraform plan with the following code but I an getting an Invalid value for module argument error.

This is the module I am using:

module “cloud-dns” {
source = “terraform-google-modules/cloud-dns/google”
version = “3.1.0”

project_id = var.gcp_project_id
type = “forwarding”

for_each = var.dns_onprem_zone

description = each.value.description
name = each.key
domain = each.value.domain
private_visibility_config_networks = [
“projects/${var.gcp_project_id}/global/networks/private-vpc-1”
]
target_name_server_addresses = each.value.forwarders

Here is the for_each block:

dns_onprem_zone = {
test-dot-com = {
description = “Forwarding”
domain = “test.com.”
forwarders = [
{
ipv4_address = “1.1.1.1”
forwarding_path = “private”
},
{
ipv4_address = “2.2.2.2”
forwarding_path = “private”
}
]
}

However when I run the tf plan I get the following error:

│ Error: Invalid value for module argument
│
│ on main.tf line 134, in module “cloud-dns”:
│ 134: target_name_server_addresses = each.value.forwarders
│
│ The given value is not suitable for child module variable
│ “target_name_server_addresses” defined at
│ .terraform/modules/cloud-dns/variables.tf:42,1-40: element 0: string
│ required.

This is the variable from the variable.tf file of the cloud-dns parent module

variable “target_name_server_addresses” {
description = “List of target name servers for forwarding zone.”
default =
type = list(map(any))

Any ideas of a fix? All help greatly appreciated.