hi everyone.
I come to this forum much but usually do not write, I like to investigate and fix things by studying the problems, but this time, I admit, I can not...
the problem is that my outgoing emails are not signed and i do not know what to do really now.
Actually the domainkeys should not be related at all, google use its internal blacklist as far as i remember or it does use CISCO senderbase.org services.
I did came up in you same situation and after a lot of investiation i didnt found anything bad on my side.. google removed my server from blacklist after about a week without action needed on my side.
You should check your server logs and different websites to check if somehow you're in some RBL's like those:
Fwd/Rev DNS Match Help Yes
Email Reputation Help Neutral
Web Reputation Help Neutral
Blacklists Help
bl.spamcop.net Not Listed
cbl.abuseat.org Not Listed
dnsbl.sorbs.net Not Listed
pbl.spamhaus.org Not Listed
sbl.spamhaus.org Not Listed
whatismyipaddress.com/blacklist-check :
all OK (green colour) except l2.apews.org (red colour)
Honestly i've no idea, may be that you were in those list two days ago and not anymore.. maybe google will take you off blacklist soon, but maybe would be needed try to find a way to contact them.