why the terraform provider param is null? It can't find in terraform repository.

[leeBT]

why the terraform provider param is null? It can't find in terraform repository.
Error: Failed to query available provider packages
│
│ Could not retrieve the list of available versions for provider hashicorp/null: provider
│ registry.terraform.io/hashicorp/null was not found in any of the search locations
│
│ - D:/DevTools/terraform/plugins

[leeBT]

terraform {
required_version = ">= 0.13.0"

required_providers {
aws = {
source = "hashicorp/aws"
version = ">= 2.0"
}
null = {
source = "hashicorp/null"
version = ">= 2.0"
}
}
}