Empty tag using module

Hello everyone, I’m testing something on terraform and I have the following directory structure.

image

When running my project everything works almost fine, except for my TAGS, it always shows up blank. here are some of my code.

modules/network/main.tf

resource "aws_internet_gateway" "igw" {
  vpc_id = aws_vpc.awslab-vpc.id
  tags = merge(local.common_tags, { Name = var.igw_name_tag })
}

resource "aws_subnet" "awslab-subnet-public" {
  cidr_block              = var.public_subnets
  vpc_id                  = aws_vpc.awslab-vpc.id
  map_public_ip_on_launch = "true"
  availability_zone       = data.aws_availability_zones.available.names[0]
  tags = merge(local.common_tags, { Name = var.subnet_public_tag })
}

prod/main.tf

module "network" {
  source  = "../modules/network"
 cidr = var.cidr
}

I have variables.tf on both modules/network and prod/

If I write everything on one main.tf everything works as excepted… any idea why this is happening?

thanks in advance