Thank you. The following is the screenshot of tech information for email that is not delivered,
https://prnt.sc/pTaN-F_JmQLl
Test email delivered to outlook.com: https://prnt.sc/DNMFl8R0mKBN
I tried different private domain emails, none are delivered. But, delivers to outlook, gmail, etc. I also moved from SES to Sendinblue, still the same issue. When I use another plugin, no issues to deliver. Thank you again!