Can other AuthSMTP users send from my domain name?
No - all domain names have to be pre-authorized on a per account basis.
To prevent abuse of our service, all from addresses and domain names have to be pre-authorized and verified before they can be used as a from address on an account.
When you authorize your from address or domain name its use is strictly limited to your account, no other user of AuthSMTP will be authorized to send from it, this is a technical limitation built into our service to protect our users.