Hi all,
Some days ago, we got a problem with sending email from our customer's domain to email of hotmail.com and outlook.com that we never met before.
When I tried to use their 2 different accounts to send an email to my Hotmail email, 1 go to Junk folder, 1 go to Inbox folder. But if send to another Hotmail account it shows the bounce back message immediately. And when trying to send again to my Hotmail, then the bounce back message appears, too.
Currently the customer is using something called Connector name: Trend Micro Hosted Email Security (Outbound) and send out through Leap.
I've checked the IP and domain reputation but all clear.
Any help or advise this case will be much appreciated. Thank you.
Your message wasn't delivered because the destination email system rejected your message for security or policy reasons. For example, the email address might only accept messages from certain senders, or it might not accept certain types of messages, like those larger than a specific size.
Contact the recipient (by phone, for example) and work with them and their email admin to determine what policy or setting blocked your message and what you should do to make sure that future messages from you won't be rejected.
For more information, see Status code 5.7.1.
The following organization rejected your message: hotmail-com.olc.protection.outlook.com.
