mutt and Return-path

[Mike Mueller <linux-support@earthlink.net>]

My new mutt install is not getting mail to all destinations. I notice that 
Return-path on mutt mails is set to an unresolvable name: myaccount@myhost. 
Could some mail nodes along the way be rejecting the mail because of the 
Return-path value? 

In .muttrc I set:
my_hdr Return-path: validname@myisp.com

Then emails started getting through.

Is there significance to the Return-path value?
-- 
Mike Mueller
324881 (08/20/2003)
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