curl --request GET \
  --url https://api-v2.missioninbox.com/relay_servers/{id}/

{
  "id": 123,
  "name": "<string>",
  "transporter_provider": "<string>",
  "transporter_key": "<string>",
  "slug": "<string>",
  "domain_count": 123,
  "mailbox_count": 123,
  "ip_addresses": [
    "<string>"
  ]
}