curl --request POST \
  --url https://api.hubapi.com/email/public/v1/smtpapi/tokens \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "createdBy": "<string>",
  "campaignName": "<string>"
}'

{
  "portalId": 123,
  "userName": "<string>",
  "emailCampaignId": 123,
  "createdAt": 123,
  "deleted": true,
  "createdBy": "<string>",
  "appId": 123,
  "campaignName": "<string>",
  "password": "<string>",
  "passwordHash": "<string>"
}