How to: obtain certificates and convert them with OpenSSL

In this blog post I gonna dive into on how to obtain certificates with Let’s Encrypt and convert them with OpenSSL.

DMARC fails in junk folder action=oreject

You have successful implemented SPF, DKIM and DMARC in your environment. But DMARC fails from your domain lands in the junk folder of an user in Exchange Online instead of rejecting it. What now?