M365 with exchange: 550 5.4.1 Recipient address rejected: Access denied.

Question

Dear experts,

We are running into a weird case where one of our domain users was using his own email account, there was no problem sending and receiving emails . However, whenever he sent his own email to himself, the email was delivered to his inbox, but along with another one from Microsoft Outlook saying
Your message to israel@X .xxx.cn couldn't be delivered.
israel wasn't found at xxx.xxx.cn

When we checked more details in that email, it said

550 5.4.1 Recipient address rejected: Access denied. AS(201806281) [xxx.prod.protection.outlook.com]   
xxxPROD.OUTLOOK.COM  

The weird part is that this email is one of our own domain accounts, we are using M365 while we synchronized users from on-premises AD environment.
Any idea or advice is appreciated.

Answer 1

@KyleXu-MSFT ,

Thanks a lot for your comments. It's figured out to be an issue with auto-forwarding function set by the user.
He set up forwarding function to forward all the emails to another one which is outside our organization, and unluckily, that account was disabled last week, which caused this issue:(

It turns out that Microsoft bounced email was not that SMART, it's not this user account not found, it was another one (forwarding to) being disabled.
Thanks again for your time!

Answer 2

@Eaven HUANG

Do you mean this account is synced from local AD, then add licenses in Microsoft 365 admin center?

If so, I want to confirm with your that whether this mailbox could send email to other mailboxes which use the same domain name? If this phenomenon occurs, I think you will need to verify this domain name on your admin center again.

I also suggest you try to send email to the default email address for this mailbox(user@keyman .onmicrosoft.com). If you could send email successfully, this phenomenon may related with the MX record for this domain.

By the way, after add domain name in Microsoft 365, I would suggest to wait for 24 hours to use it.

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