Kami mendapati error seperti ini

2022-06-15 14:54:35 1o1NrG-0002Yw-9b DKIM: validation error: error:04091077:rsa routines:INT_RSA_VERIFY:wrong signature length
2022-06-15 14:54:35 1o1NrG-0002Yw-9b H=sender4-of-o51.zoho.com [136.143.188.51] Warning: DKIM: Failed. reason='signature_incorrect'
2022-06-15 14:54:35 1o1NrG-0002Yw-9b H=sender4-of-o51.zoho.com [136.143.188.51] X=TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no F=<nunung@teaaaa.co.id> rejected after DATA: Your message to <deve@aaa.co.id, kasman@aaa.co.id> was classified as SPAM.  Please add more content, cut down on HTML links, use fewer naughty words etc.  Also, ask your IT dept to make sure your mailserver has REVERSEDNS, SPF, DKIM, and is not on any black lists. Your score: 100

biasanya terjadi karena ketidak sesuaian SPF, tapi kali ini disebabkan ip address zohonya yang mati, hal ini terbukti dari

#ping 136.143.188.51
PING 136.143.188.51 (136.143.188.51) 56(84) bytes of data.
^C
--- 136.143.188.51 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2268ms

dan test telnet pun tidak bisa

#telnet 136.143.188.51 25
Trying 136.143.188.51...

jadi kesimpulannya email tersebut ditolak disebabkan ip server pengirim down.