Can’t Send Intranet and SMTP e-mail

Having trouble sending Intranet and SMTP mail -(in OUTLOOK 98) at the same time- the internal e-mail will come back as:

-System Administrator – Undeliverable
-The originator does not have permission to
submit message
-MSEXCH:MSExchangeIS:GOWMAC:GMSR1

Have try going into Outlook under tool,services, deliverty tab and change the order of the information services – still have the same problemm

Thank you for your assistance.