Terraform giving error for new AWS new regions (af-south-1,eu-south-1)

I am facing issue while creating resources in aws account using terraform script (0.11 version)

changes in main.tf file =>

provider "aws" {
alias = "af-south-1"
region = "af-south-1"
}

module "af-south-1-module" {
  source = "./modules"
  providers = {
    aws = "aws.af-south-1"
  }
 aws_region= "af-south-1"
 should_run= "${contains(var.region_list, "af-south-1")}"
 customer_id= "${var.customer_id}"
 dns_prefix= "${var.dns_prefix_flowlogs}"
 iam_for_lambda_arn= "${aws_iam_role.iam_for_lambda.arn}"
 aws_account_id= "${local.aws_account_id}"
 iam_for_vpc_flow_arn= "${aws_iam_role.avid_vpc_flow_role.arn}"
 }

changes in vars.tf file =>

    variable "region_list" {
    type = "list"
    default = ["us-west-1",
    "us-west-2",
    "us-east-1",
    "eu-north-1",
    "af-south-1"]
   }

I am getting following error while running "terraform apply" command

Error: Error refreshing state: 2 error(s) occurred:

• provider.aws.eu-south-1: Invalid AWS Region: eu-south-1
• provider.aws.af-south-1: Invalid AWS Region: af-south-1

Note:

1. Region is enabled in AWS account
2. Same code is working for other regions in region_list.