Strange localhost.localdomain

Hi,

after having used exmh for years I received now a complain that in MS outlook 
express when the reply button is clicked to my mail it shows 
[email protected] and naturally bounces back when send.

this is what the header in the mail of outlook express shows:

-----Original Message-----
From: Peter [mailto:[email protected]] 
Sent: Friday, February 24, 2006 11:38 AM

Sending mail using sylpheed it shows the correct e-mail address of mine.

How can I correct this in exmh?

and trying to send this mail with exmh I just got a bounce:

 ----- The following addresses had permanent fatal errors -----
<[email protected]>
    (reason: 554 5.7.1 Go away. localhost.localdomain is not accepted here.)

with headers showing:

From: Peter <[email protected]>
To: [email protected]
Date: Sun, 26 Feb 2006 10:56:59 +0800
X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.0.4

I therefore resend this mail with sylpheed.

Thanks & regards
-- 
Peter

-- 
Peter