Problem with sending e-mails to Fedora mailing list

[Bukovansky Richard]

Hi,
I'm not sure I asking the right group, but I need help.
When I send an e-mail to any Fedora mailing list I'm subscribed to, my
e-mails are not delivered back to me even I have set "Receive your own
posts to the list?" to yes. My e-mail is delived to everybody in the
list, it's showing in mailing list archive. I.e.:
https://www.redhat.com/archives/fedora-cs-list/2007-August/msg00073.html

What is suprising me more, I'm getting this kind of error e-mails back
after while:

This is the Postfix program at host smtp-out4.iol.cz.

####################################################################
# THIS IS A WARNING ONLY.  YOU DO NOT NEED TO RESEND YOUR MESSAGE. #
####################################################################

Your message could not be delivered for 8.0 hours.
It will be retried until it is 5.0 days old.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

			The Postfix program

<fedora-cs-list at rehdat.com>: connect to rehdat.com[208.73.212.12]:
Connection refused

Or once I got this one:

This is the Postfix program at host smtp-out3.iol.cz.

####################################################################
# THIS IS A WARNING ONLY.  YOU DO NOT NEED TO RESEND YOUR MESSAGE. #
####################################################################

Your message could not be delivered for 8.0 hours.
It will be retried until it is 5.0 days old.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

			The Postfix program

<fedora-cs-list at rehdat.com>: connect to rehdat.com[69.25.212.153]:
Connection timed out



It was working normally before and I'm not sure what can be wrong.

Thank you very much.

-- 
Bukovansky Richard
richard.bukovansky at atlas.cz