List bouncing my emails - what's up?

[mardak at gmail.com (Mark F.)]

>From my <mk1mark@gmail.com> address I get the following delivery notice when
I send an email to the list:

---------------------------------------------------------------------------------------
Delivery to the following recipient failed permanently:

scirocco-l@scirocco.org

Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 9): 550 Server Down
---------------------------------------------------------------------------------------

I tried three times throughout the day today, and got the same result each
time. Anyone know why?

Thanks!

Mark.
75
80 S
86
90 Audi Coupe Quattro - 10vt