smtp server problem

 
Hello,

I've been trying to use another smtp and I have been getting this message:
Mail: 553 sorry, that domain isn't allowed to be relayed thru this MTA (#5.7.1)
I think that that is some problem correlated with time out.

Any help is must appreciated,
 

Not time-out.

The error says "that domain isn't allowed to be relayed thru this MTA"

The mail server you connected to does not relay non-local mail

 
phy:

Not time-out.

The error says "that domain isn't allowed to be relayed thru this MTA"

The mail server you connected to does not relay non-local mail

I know that that is a kind of off-topic, but just a curiosity: what does a "non-local mail" mean or what is that?

Thanks a lot,