error 553 Relaying disallowed

error 553 Relaying disallowed

Hi,

I'm new to Zoho. I've looked at some other threads and I have my mailbox enabled in the domain settings, I have the same email address in the "send mail as" settings in Zoho as I do in my outlook. I'm using outgoing smtp port 465, SSL and box ticked for "This server requires an encrypted connection" and also on the the "Outgoing server" tab I have ticked "My outgoing server (SMTP) requires authentication.

I still get the error those after making those changes.