When sending email to certain address we are receiving back a 550 Requested action not taken: mailbox unavailable. Below is the log from Misc Events05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: Attempting to Connect: Host xxxxxx-com.mail.eo.outlook.COM, Port 25, SSL Port 0, Connecting Domain xxx…xxxxx.com
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: Connection successful
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 220 TX2EHSMHS015.xxxxx.com ESMTP Service ready
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: CommandEHLO: EHLO xxxx.xxxxx.com
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250-Requested mail action okay, completed
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250-SIZE 157286400
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250-8BITMIME
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250 OK
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: Attempting to SubmitMessage:
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: CommandMAIL: MAIL FROM:xxxxx@xxxxx.com SIZE=5710
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250 Requested mail action okay, completed
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: CommandRCPT: RCPT TO:xxxx@xxxxxx.com
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 550 Requested action not taken: mailbox unavailable
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: CommandRSET:
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 250 Requested mail action okay, completed
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: Attempting to Disconnect:
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: CommandQUIT:
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: ReceiveResponse: 221 Service closing transmission channel
05/08/2012 10:07:25 AM [18873:00033–735528032] SMTPClient: Connection terminated successfully
05/08/2012 10:07:25 AM Router: Transferred 1 messages to xxxxxxxx.COM (host xxxxxxxx-com.mail.eo.outlook.COM) via SMTP
can any decipher and help with this issue?
Thanks
Theresa