Email delivery failure, error 550 5.7.1

When user sending internal company emails, emails get thru, but when she send email to outside email (hotmail, gmail, etc…), getting delivery failure- error transfering to… invalid mailbox. I tried to send to few users and all failed same way. error…:


“Error transfering to loninmrp8-i.uk.DB.COM; SMTP Protocol Returned a Permanent Error 550 5.7.1 xxx@xx.com Invalid mailbox”.

What i noticed is that from outside i cant send her emails either. The mail box can receive and send only inside (company )emails. This is the message i got when i tried to send her email from outside: " The following recipient(s) could not be reached:

xxx@xx.com on 2/4/2009 2:05 PM

You do not have permission to send to this recipient. For assistance, contact your system administrator.

< xxx@xx.com #5.7.1 SMTP; 550 5.7.1 xxx@xx.com… Invalid mailbox>"

Please help…

Subject: email delivery failure, error 550 5.7.1

Check the link below

http://www.ibm.com/support/docview.wss?rs=899&uid=swg21090529

Check the location document of user for the internet address … or check the configuration document → MIME → Cpnversion Option → Outbound → Lookup internet addresses for all notes addresses when internet address is not defined…