const response = await fetch('/api/MailboxSettings/Test', {
    method: 'POST',
    headers: {
      "Content-Type": "application/json; api-version=1.0"
    },
    body: JSON.stringify({
      "email": "text"
    }),
});
const data = await response.json();

{
  "type": "text",
  "title": "text",
  "detail": "text",
  "instance": "text"
}

const response = await fetch('/api/MailboxSettings', {
    method: 'PUT',
    headers: {
      "Content-Type": "application/json; api-version=1.0"
    },
    body: JSON.stringify({}),
});
const data = await response.json();

{
  "type": "text",
  "title": "text",
  "detail": "text",
  "instance": "text"
}

const response = await fetch('/api/MailboxSettings', {
    method: 'GET',
    headers: {},
});
const data = await response.json();

{
  "useTLS": [
    "0 = No",
    "1 = Yes",
    "2 = YesIfAvailable",
    "3 = YesTLS12IfAvailable"
  ],
  "requireAuth": false,
  "smtpServer": "text",
  "senderAddress": "text",
  "username": "text"
}