One user can not send email out

[JohnnyMc509]

I am new to Exchange, we are actually using version 5.0 I have one user that is setup for internet email but when she sends out she gets the following message:

The following recipients did not receive the attached mail. Reasons are listed with each recipient:

<COMPLETE@SSSNET.COM> COMPLETE@SSSNET.COM
MSEXCH:IMS:VNSA:Corp:VNS_NT1 0x80070057 (0005029B) Conversion to internet format failed

Anyone know what would cause this?
Your ideas are greatly appreciated!

 

[click]

Try to see if this is an HTML or rich text format, and if so, there might be a restriction on the ineternet mail service, check with the BOadministrator program, under the connections>internet mail service>advanced options. Click

 

[JohnnyMc509]

This employee is using rich text. I switched to plain text and still could not send outside email. She is the only person having a problem and she says it has been like this since she got the PC. She has no problem with interoffice email.