REvising the post I noticed it's a bit confusing. So I decided to summarize as bellow.
# 1. Body as text/plain and email goes through;
Nov 10 12:41:35 evex postfix/smtp[29497]: 671A75196F: to= < iuri.sampaio @ gmail.com > , relay=smtpout.secureserver.net[173.201.192.229]:465, delay=0.47, delays=0.06/0.01/0.29/0.1, dsn=2.0.0, status=sent (250 L
# 2. Body as text/html and email bounces;
MX records are properly created. As well as SPF, DKIM and _DMARC records.
Godaddy complains about the logo within the html body. I removed the logo, but the email still gets rejected.
Nov 10 12:34:43 evex postfix/smtp[29372]: DBBC751954: to= < bounce-1700-72FE66917C917C25B5DCEDC1D79304D1B78EE324-336 @ mail.evex.co >, relay=smtpout.secureserver.net[68.178.252.101]:465, delay=0.34, delays=0.01/0/0.21/0.13, dsn=5.0.0, status=bounced (host smtpout.secureserver.net[68.178.252.101] said: 550 <> Sender Rejected - MAILFROM must be a valid domain. Ensure the mailfrom domain: "" has a valid MX or A record. (in reply to end of DATA command))