553 Relaying disallowed

553 Relaying disallowed

I was trying to setup an account on outlook, the pop3 connection was OK, but the stmp failed and shows a "553 Relaying disallowed". What this mean? How can I solve it?

Already have about 5 acoounts within this domain setup without problems, but

the outgoing server name used is smtp.zoho.com / SSL / port 465, and the emai is "mramirez on seiconsultores dot cl"

thanks!