"Mail not sent... sorry that domain....

"Mail not sent... sorry that domain isnt inmy list of recipant hosts" something happened to my mail confix postfix/main.cf I suppose my machine name is Serina and my provider cps92.com somehow postfix is looking for a list of qualified receiptants OR SuSE is bouncing my messages. I can send send mail out to myself... but I never receive it ;-/ However I *can* get mail from the list Ive switched to Postfix and It worked for a while... but something changed (Im not sure what) and the damm thing dosnt work. Ive rea the docs and the more I look... the more complex it seems. Like I say I have 2 parameters mymachine name = Serina local 10.xxx address myactual_provider