(I accidently made a mistake and closed firefox this is a contimuation)
.
Is it possible this problem has somethin g to do with DMARC(SPF,DKIM)
IN the mails I still received before 4 december I see the following in the headers:
of a lot of the mails (especiallyt from those using a gmail address):
Authentication-Results: mail.iss.as9143.net; spf=pass (38.145.60.11;lists.fedoraproject.org); dkim=none (nosigs); dmarc=fail header.from=gmail.com (p=none sp=quarantine dis=monitor)
I know next to nothing about DMARC but I suspect that Ziggo was monitoring this and then
about 4-5 december decided to 'activate' it.
Could you please investigate

I need to know what mailing address you are wanting this email to. A lot of people use different emails from their fas account on the lists. I also need to know which list you are not seeing email from.

Wait I see the problem. mail.iss.as9143.net. That is the upstream of Virgin communications and it has been dropping mail from us since at least Dec 01

Dec  1 17:56:56 bastion01 postfix/smtp[2948937]: 09C6730995F6: to=<...>, relay=mx.tb.ukmail.iss.as9143.net[212.54.56.11]:25, delay=6906, delays=686
8/38/0.2/0, dsn=4.0.0, status=deferred (host mx.tb.ukmail.iss.as9143.net[212.54.56.11] refused to talk to me: 421 mx3.tb.ukmail.iss.as9143.net mx3.tb.ukmail.iss.as9143.net MXIN107 Connection
s from your IP 38.145.60.11 have been disallowed by admin policy. ;id=k9tYkc7ajyjlh;sid=k9tYkc7ajyjlh;mta=mx3.tb;d=20201201;t=185656[CET];ipsrc=38.145.60.11;)

Any domains served by

   3924 home.nl
   3232 ziggo.nl
   2084 ntlworld.com
   1774 quicknet.nl
   1678 blueyonder.co.uk

are affected. I have looked for a way to communicate this problem to the provider but it seems only people who are customers can do so. You will need to open a ticket with ziggo and let them know.

Sorry for the incomplete message. I made a mistake and then I forgot to add the part describing
my problem. I mail to the mailing lists user/test of lists.fedoraproject.org using the
address < volovics@ziggo.nl>.
So indeed domain ziggo.nl
Do you have any idea why this is happening. Does it have anything to do with their DMARC
policy?

I shall try to take this up with Ziggo tomorrow.

I don't know if this helps, hopefully yes ....
This issue comes from Fedora users list thread "no mail from users/test lists since about 5 days". Here's a link:
"https://lists.fedoraproject.org/archives/list/users@lists.fedoraproject.org/thread/35UYBPHSJLQH6554JMIT5WZVTVI22J73/".
It was I (users list name = "home user") that recommended that "AV" open an issue here.

"Der": If this issue cannot be solved for your ziggo e-mail address, can you change the e-mail address to which fedora users list posts are sent?

NB: Der=volovics@ziggo.nl (I opened a gmail account to join FAS)
Thanks for the replies. The problem is solved. I had been pestering Ziggo
with phone calls and emails and this afternoon I received an email from them
stating:

The following ip block was blacklisted by Ziggo on the mailservers as a last resort
antispam measure and it seems at least 2 ip adresses from lists.fedoraproject.org
were contained in it. This blockade has been lifted and everything should be
working normally again.
Network: 38.0.0.0/8
HostMin: 38.0.0.1
HostMax: 38.255.255.254
Hosts/Net: 16777214 Class A

Indeed I can receive list mails again (till the next drastic Ziggo measure?)

wow a /8 blockade is quite a bit. Thanks for doing that.