Gmail as of now is not supporting DKIM with with Punnycode@punnycode email address, considers them invalid. See the requests below.
DKIM Fail example -
Delivered-To: deepakdeepaksinghal@gmail.com
Received: by 10.28.186.67 with SMTP id k64csp240680wmf;
Fri, 2 Dec 2016 02:11:10 -0800 (PST)
X-Received: by 10.99.60.11 with SMTP id j11mr78479662pga.26.1480673468504;
Fri, 02 Dec 2016 02:11:08 -0800 (PST)
Return-Path: <депак@почта.рус>
Received: from tbms.xn--80a1acny.xn--p1acf (tbms.xn--80a1acny.xn--p1acf. [212.109.217.59])
by mx.google.com with UTF8SMTP id z97si4494171plh.165.2016.12.02.02.11.06
for <deepakdeepaksinghal@gmail.com>;
Fri, 02 Dec 2016 02:11:08 -0800 (PST)
Received-SPF: pass (google.com: domain of депак@почта.рус designates 212.109.217.59 as permitted sender) client-ip=212.109.217.59;
Authentication-Results: mx.google.com;
dkim=neutral (bad format) header.i=@xn--80a1acny.xn--p1acf;
spf=pass (google.com: domain of депак@почта.рус designates 212.109.217.59 as permitted sender) smtp.mailfrom=депак@почта.рус
DKIM-Signature: v=1; a=rsa-sha1; q=dns/txt; c=simple/relaxed; t=1480673464; s=xgen; d=почта.рус; h=Date:From:Message-ID:MIME-Version; z=Date:Fri,=202=20Dec=202016=2014:11:04=20+0400=20(GMT+04:00)|From:=D0=B4=D0=B5=D0=BF=D0=B0=D0=BA<=D0=B4=D0=B5=D0=BF=D0=B0=D0=BA@=D0=BF=D0=BE=
=D1=87=D1=82=D0=B0.=D1=80=D1=83=D1=81>|Message-ID: <1602962842.151480673464388.JavaMail.root@ct301>|MIME-Version:1.0; l=1078; bh=LYJgeY6BTAyJEdFJM0FhV4tcBAc=; b=PMYrmgxtx4s4lUyFP6Kp50xW8bmbUP6MbozwsdSdnZrOd4kR52MtDSRuK4RJZVoS jm5rg+6ht2M1cFdYCQtcRE2DNKF94LaiVSNMy6IScjnCZNT0RnQ0tfWvt+9qiQLWURJ fEblIhSIrNzWLiSbShrEnbAv4+6eOoK8krb1UTeI=
Return-path: депак@почта.рус
Date: Fri, 2 Dec 2016 14:11:04 +0400 (GMT+04:00)
From: "депак" <депак@почта.рус>
To: deepakdeepaksinghal@gmail.com
Message-ID: <1602962842.151480673464388.JavaMail.root@ct301>
Subject: deepakdeepaksinghal@gmail.com
Errors-to: <поддержка@почта.рус>
MIME-Version: 1.0
DKIM Pass Example-
Delivered-To: deepakdeepaksinghal@gmail.com
Received: by 10.28.186.67 with SMTP id k64csp239355wmf;
Fri, 2 Dec 2016 02:08:05 -0800 (PST)
X-Received: by 10.25.29.8 with SMTP id d8mr13960908lfd.18.1480673285872;
Fri, 02 Dec 2016 02:08:05 -0800 (PST)
Return-Path: <admin@почта.рус>
Received: from tbms.xn--80a1acny.xn--p1acf (tbms.xn--80a1acny.xn--p1acf. [212.109.217.59])
by mx.google.com with UTF8SMTP id b78si2265194lfh.395.2016.12.02.02.08.05
for <deepakdeepaksinghal@gmail.com>;
Fri, 02 Dec 2016 02:08:05 -0800 (PST)
Received-SPF: pass (google.com: domain of admin@почта.рус designates 212.109.217.59 as permitted sender) client-ip=212.109.217.59;
Authentication-Results: mx.google.com;
dkim=pass header.i=@почта.рус;
spf=pass (google.com: domain of admin@почта.рус designates 212.109.217.59 as permitted sender) smtp.mailfrom=admin@почта.рус
DKIM-Signature: v=1; a=rsa-sha1; q=dns/txt; c=simple/relaxed; t=1480673284; s=xgen; d=почта.рус; h=Date:From:Message-ID:MIME-Version; z=Date:Fri,=202=20Dec=202016=2014:08:04=20+0400=20(GMT+04:00)|From:admin<admin@=D0=BF=D0=BE=D1=87=D1=82=D0=B0.=D1=80=D1=83=D1=81>|Message-ID:<1550206923.111480673284389.JavaMail.root@ct301>|MIME-Version:1.0; l=1164; bh=h5oHHzyPgSAt3/D+KrbGVAKW9V8=; b=15ZCXJ+6ZBfD8JfTSp1TO9MoBhoWps3o+aWosp/G+avM+tuMTYoKEuY/Bcvx57kF 1de1zbQO+pDcnkonADj4c9hLRv8hLwU2Kv1UxyFl6yJQ9CaoJNxOIA2YtsEiEVPM8s/ j8Ewi3H42FrOoBycL+WY8GtTgWLgb2eKBqY405ug=
Return-path: admin@почта.рус
Date: Fri, 2 Dec 2016 14:08:04 +0400 (GMT+04:00)
From: admin <admin@почта.рус>
To: <deepakdeepaksinghal@gmail.com>
Message-ID: <1550206923.111480673284389.JavaMail.root@ct301>
Subject: hello Sir1
Errors-to: <поддержка@почта.рус>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="----=_Part_5_1869815482.1480673284388"
X-Mailer: XGen Plus INSTANT MESSAGING SYSTEM
X-ScheduledMail: FALSE