554 Sorry, no mailbox here by that name

I don't know why this e-mail forms processor will not work. I get the folloowing error back.
The message was undeliverable. All servers failed to receive the message
.execute()
{
Trying server mail:mail.gamenw.org
<- 220 xmail02.myhosting.com ESMTP 648143d3667b3045487bb901cdbbf649
-> EHLO web4008.ad1.softcom.biz
<- 250-xmail02.myhosting.com
250-PIPELINING
250-SIZE 100000000
250-DATAZ
250-STARTTLS
250-AUTH LOGIN PLAIN
250 8BITMIME
-> MAIL FROM:
<- 250 ok
-> RCPT TO:jerry.miller@gamenw.org
<- 554 Sorry, no mailbox here by that name. (#5.1.1)
-> DATA
Error: Connection reset by client.
.execute()
{
Trying server mail:mail.gamenw.org
<- 220 xmail02.myhosting.com ESMTP 648143d3667b3045487bb901cdbbf649
-> EHLO web4008.ad1.softcom.biz
<- 250-xmail02.myhosting.com
250-PIPELINING
250-SIZE 100000000
250-DATAZ
250-STARTTLS
250-AUTH LOGIN PLAIN
250 8BITMIME
-> MAIL FROM:
<- 250 ok
-> RCPT TO:jerry.miller@gamenw.org
<- 554 Sorry, no mailbox here by that name. (#5.1.1)
-> DATA
Error: Connection reset by client.

1 of 1 servers failed
}
Now whn i put in an recieving e-mail such as a hotmail or g-mail or yahoo, it works just fine. the gamenw.org e-mail do exist
Any ideas would help