Created attachment 341646 [details] mxtoolbox.com output It seems like smtp.gentoo.org is reported as blacklisted on http://mxtoolbox.com. Attached is an image verifying this. The problem is that SMTP servers using this website to verify the integrity of an MX server can't email Gentoo people. I fact, I used my work address to email my gentoo address and never got that email. Could you have a look please?
smtp.g.o is only blacklisted on BACKSCATTERER; mxtoolbox.com is just an aggregator. The history on that bl for our IP shows frequent blacklisting going back to 2007. Their policy is to blacklist for 4 weeks, or to extort money for "expedited" removal. I assert it's not worth the 111USD they are asking. As for your work email issues, please open a different bug with debugging information[timestamps, sending account name, originating mailserver, ...]