title: Terraform returns 500 on MongoDB Atlas cluster creation
body: <p>Terraform gives back an error when I create a cluster for MongoDB Atlas. I have a premium Mongo account and creation of other resources like mongodb_container, database_user, atlas_project etc worked with TF. But for cluster creation, I get the error posted below.</p>
  <pre><code>Error: error creating MongoDB Cluster: POST https://cloud.mongodb.com/api/atlas/v1.0/groups/606391c736b8af0a227cb763/clusters: 500 (request &quot;UNEXPECTED_ERROR&quot;) Unexpected error.
      
    on atlas-infra.tf line 20, in resource &quot;mongodbatlas_cluster&quot; &quot;test-cluster&quot;:
    20: resource &quot;mongodbatlas_cluster&quot; &quot;test-cluster&quot; {
  </code></pre>
  <p>Here my script for cluster resource:</p>
  <pre><code>resource &quot;mongodbatlas_cluster&quot; &quot;test-cluster&quot; {
    project_id   = mongodbatlas_project.test_db.id
    name         = &quot;test-cluster&quot;
    cluster_type = &quot;REPLICASET&quot;
    replication_specs {
      num_shards = 1
      regions_config {
        region_name     = var.atlas_region
        electable_nodes = 1
        priority        = 7
        read_only_nodes = 0
      }
    }
    provider_backup_enabled      = true
    auto_scaling_disk_gb_enabled = true
    mongo_db_major_version       = &quot;4.2&quot;
  
    //Provider Settings &quot;block&quot;
    provider_name               = &quot;GCP&quot;
    disk_size_gb                = 10
    provider_instance_size_name = &quot;M10&quot;
  }
  </code></pre>