Cant not use Selfhost S3 as backend

i want to use s3 as my backend storage
how even i am using selfhost s3 intergrade with StorageGird.

backend “s3” {

bucket = "terraform-backend-statusfile"

key    = "terraform.tfstate"

region = "region_name"

endpoint = ""

access_key = "Key"

secret_key = "Secret"

when i try to init terrafomr

Initializing the backend…
Error: Invalid AWS Region: “region_name”

Howeven i can login to AWS cli by using upper information