[SOLVED] terraform elasticsearch: invalid value for domain

I got errors below:

Error: invalid value for domain_name (must start with a lowercase alphabet and be at least 3 and no more than 28 characters long. Valid characters are a-z (lowercase letters), 0-9, and - (hyphen).)

on .terraform/modules/elasticsearch/main.tf line 100, in resource "aws_elasticsearch_domain" "default": 100: domain_name = module.this.id

Here are the source code. main.tf:

module "elasticsearch" {
  source                  = "git::https://github.com/cloudposse/terraform-aws-elasticsearch.git?ref=tags/0.24.1"

  security_groups                = [data.terraform_remote_state.vpc.outputs.default_security_group_id]
  vpc_id                         = data.terraform_remote_state.vpc.outputs.vpc_id
  subnet_ids                     = data.terraform_remote_state.vpc.outputs.private_subnets
  zone_awareness_enabled         = var.zone_awareness_enabled
  elasticsearch_version          = var.elasticsearch_version
  instance_type                  = var.instance_type
  instance_count                 = var.instance_count
  encrypt_at_rest_enabled        = var.encrypt_at_rest_enabled
  dedicated_master_enabled       = var.dedicated_master_enabled
  create_iam_service_linked_role = var.create_iam_service_linked_role
  kibana_subdomain_name          = var.kibana_subdomain_name
  ebs_volume_size                = var.ebs_volume_size
  #dns_zone_id                    = var.dns_zone_id
  kibana_hostname_enabled        = var.kibana_hostname_enabled
  domain_hostname_enabled        = var.domain_hostname_enabled

  advanced_options = {
    "rest.action.multi.allow_explicit_index" = "true"
  }

  context = module.this.context
}

data.tf:

provider "aws" {
  version = "3.20.0" 
  region  = var.region
}

context.tf:

module "this" {
  source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=tags/0.22.0"

  enabled             = var.enabled
  namespace           = var.namespace
  environment         = var.environment
  stage               = var.stage
  name                = var.name
  delimiter           = var.delimiter
  attributes          = var.attributes
  tags                = var.tags
  additional_tag_map  = var.additional_tag_map
  label_order         = var.label_order
  regex_replace_chars = var.regex_replace_chars
  id_length_limit     = var.id_length_limit

  context = var.context
}

variable "context" {
  type = object({
    enabled             = bool
    namespace           = string
    environment         = string
    stage               = string
    name                = string
    delimiter           = string
    attributes          = list(string)
    tags                = map(string)
    additional_tag_map  = map(string)
    regex_replace_chars = string
    label_order         = list(string)
    id_length_limit     = number
  })
  default = {
    enabled             = true
    namespace           = null
    environment         = null
    stage               = null
    name                = null
    delimiter           = null
    attributes          = []
    tags                = {}
    additional_tag_map  = {}
    regex_replace_chars = null
    label_order         = []
    id_length_limit     = null
  }
  description = <<-EOT
    Single object for setting entire context at once.
    See description of individual variables for details.
    Leave string and numeric variables as `null` to use default value.
    Individual variable settings (non-null) override settings in context object,
    except for attributes, tags, and additional_tag_map, which are merged.
  EOT
}

variable "enabled" {
  type        = bool
  default     = true
  description = "Set to false to prevent the module from creating any resources"
}

variable "namespace" {
  type        = string
  default     = "dev"
  description = "Namespace, which could be your organization name or abbreviation, e.g. 'eg' or 'cp'"
}

variable "environment" {
  type        = string
  default     = "dev-blue"
  description = "Environment, e.g. 'uw2', 'us-west-2', OR 'prod', 'staging', 'dev', 'UAT'"
}

variable "stage" {
  type        = string
  default     = "dev-blue"
  description = "Stage, e.g. 'prod', 'staging', 'dev', OR 'source', 'build', 'test', 'deploy', 'release'"
}

variable "name" {
  type        = string
  default     = "es-nsm-blue"
  description = "Solution name, e.g. 'app' or 'jenkins'"
}

variable "delimiter" {
  type        = string
  default     = "-"
  description = <<-EOT
    Delimiter to be used between `namespace`, `environment`, `stage`, `name` and `attributes`.
    Defaults to `-` (hyphen). Set to `""` to use no delimiter at all.
  EOT
}

variable "attributes" {
  type        = list(string)
  default     = []
  description = "Additional attributes (e.g. `1`)"
}

variable "tags" {
  type        = map(string)
  default     = {}
  description = "Additional tags (e.g. `map('BusinessUnit','XYZ')`"
}

variable "additional_tag_map" {
  type        = map(string)
  default     = {}
  description = "Additional tags for appending to tags_as_list_of_maps. Not added to `tags`."
}

variable "label_order" {
  type        = list(string)
  default     = null
  description = <<-EOT
    The naming order of the id output and Name tag.
    Defaults to ["namespace", "environment", "stage", "name", "attributes"].
    You can omit any of the 5 elements, but at least one must be present.
  EOT
}

variable "regex_replace_chars" {
  type        = string
  default     = null
  description = <<-EOT
    Regex to replace chars with empty string in `namespace`, `environment`, `stage` and `name`.
    If not set, `"/[^a-zA-Z0-9-]/"` is used to remove all characters other than hyphens, letters and digits.
  EOT
}

variable "id_length_limit" {
  type        = number
  default     = null
  description = <<-EOT
    Limit `id` to this many characters.
    Set to `0` for unlimited length.
    Set to `null` for default, which is `0`.
    Does not affect `id_full`.
  EOT
}

terraform elasticsearch: invalid value for domain_name