Q:

Mailman: Is it possible to re-send bounced emails? 

I've just installed a Mailman server to send newsletters, but I (foolishly) didn't wait long enough for the new dedicated subdomain to propagate through the DNS network before sending the first one, so now I have a lot of bounced emails :( (due to Sender address rejected: Domain not found (in reply to RCPT TO command))
Since about half of the emails went through anyway, is it possible to tell Mailman to re-send the bounced ones, now that the DNS issue is settled? 
Here's the Postfix log for one of those bounced emails:
Oct 30 10:07:02 localhost postfix/smtpd[28548]: 47C5EC4134: client=localhost[127.0.0.1]
Oct 30 10:07:02 localhost postfix/cleanup[28580]: 47C5EC4134: message-id=<5451FFA8.8010408@XXX.com>
Oct 30 10:07:02 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, size=431670, nrcpt=1 (queue active)
Oct 30 10:07:02 localhost postfix/smtp[28562]: 47C5EC4134: to=<info@icos-group.it>, relay=smtp. XXX.com[XX.XXX.X.XXX]:25, delay=0.42, delays=0.05/0/0.21/0.16, dsn=4.1.8, status=deferred (host smtp. XXX.com[XX.XXX.X.XXX] said: 450 4.1.8 <lista_clienti-bounces@lists.XXX.com>: Sender address rejected: Domain not found (in reply to RCPT TO command))
Oct 30 10:16:20 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, size=431670, nrcpt=1 (queue active)
Oct 30 10:16:20 localhost postfix/smtp[29719]: 47C5EC4134: to=<info@icos-group.it>, relay=smtp. XXX.com[XX.XXX.X.XXX]:25, delay=558, delays=558/0.06/0.1/0.04, dsn=4.1.8, status=deferred (host smtp. XXX.com[XX.XXX.X.XXX] said: 450 4.1.8 <lista_clienti-bounces@lists.XXX.com>: Sender address rejected: Domain not found (in reply to RCPT TO command))
Oct 30 10:26:20 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, size=431670, nrcpt=1 (queue active)
Oct 30 10:26:20 localhost postfix/smtp[30860]: 47C5EC4134: to=<info@icos-group.it>, relay=smtp. XXX.com[XX.XXX.X.XXX]:25, delay=1159, delays=1158/0.03/0.34/0.05, dsn=4.1.8, status=deferred (host smtp. XXX.com[XX.XXX.X.XXX] said: 450 4.1.8 <lista_clienti-bounces@lists.XXX.com>: Sender address rejected: Domain not found (in reply to RCPT TO command))
Oct 30 10:46:20 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, size=431670, nrcpt=1 (queue active)
Oct 30 10:46:21 localhost postfix/smtp[320]: 47C5EC4134: to=<info@icos-group.it>, relay=smtp. XXX.com[XX.XXX.X.XXX]:25, delay=2359, delays=2359/0.03/0.1/0.04, dsn=4.1.8, status=deferred (host smtp. XXX.com[XX.XXX.X.XXX] said: 450 4.1.8 <lista_clienti-bounces@lists.XXX.com>: Sender address rejected: Domain not found (in reply to RCPT TO command))
Oct 30 11:16:20 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, size=431670, nrcpt=1 (queue active)
Oct 30 11:16:20 localhost postfix/smtp[3133]: 47C5EC4134: to=<info@icos-group.it>, relay=smtp. XXX.com[XX.XXX.X.XXX]:25, delay=4158, delays=4158/0.03/0.1/0.06, dsn=4.1.8, status=deferred (host smtp. XXX.com[XX.XXX.X.XXX] said: 450 4.1.8 <lista_clienti-bounces@lists.XXX.com>: Sender address rejected: Domain not found (in reply to RCPT TO command))
Oct 30 11:16:20 localhost postfix/qmgr[14515]: 47C5EC4134: from=<lista_clienti-bounces@lists.XXX.com>, status=expired, returned to sender
Oct 30 11:16:20 localhost postfix/bounce[3136]: 47C5EC4134: sender non-delivery notification: 9CFC2C0560
Oct 30 11:16:20 localhost postfix/qmgr[14515]: 47C5EC4134: removed

A:

Usually the error message
Sender address rejected: Domain not found (in reply to RCPT TO command)

indicated this is temporary error because of non-existent domain.  DNS change usually propagate in 24 hours and by default postfix should automatically retry this delivery until maximal_queue_lifetime (the default value is 5 days). 
As you accidentally set maximal_queue_lifetime to 1 hour, then postfix will give up after retried for 1 hour.  Then postfix will send bounces to mailman. 
Because of that you need to resend email to mailman.  If you have configured archive in mailman list, then you can retrieve the original email there.