Exchnage Hybrid and distribution list

sim3vi 166 Reputation points
2022-07-11T07:00:21.65+00:00

In an Exchange hybrid environment 60% of mailbox are migrated to 365. All the distribution list are on prem. I try to "migrate" the dl on cloud by this steps:
On prem I extract the members and copy the X500 address.
Delete the dl.
Sync by ad connect to 365
Create a new dl with the same email address, add the members and copy the X500 address.
If I try to send a email from on prem to migrated dl I receive an error "Remote Server returned '550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup'".

Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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  1. Andy David - MVP 152.1K Reputation points MVP
    2022-07-12T14:13:23.647+00:00
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  1. Andy David - MVP 152.1K Reputation points MVP
    2022-07-11T11:23:58.18+00:00

    You should wait till all the mailboxes are in 365 and all message traffic is between the 365 mailboxes and the 365 groups.
    Its failing from on-prem because the SMTP domain in on-prem Exchange is authoritative and doesnt know how to route to the group in 365 since that email address is no longer on-prem.


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