email alert configuration error

 

Hello,

I`m getting this error :

mail:553 5.5.4 <advisor> ... Domain name required for recipients address

I've checked all my smtp parameters, etc .. all seems correct the recipients address works just fine ( it`s a yahoo one ) . 

In the "to" section there is definitely "@yahoo.com" .

Does anybody know what I`m doing wrong ? It seems pretty silly but I can`t figure out what's going on ...

Cheers,