Jan 26 2023 10:42 AM
Hi Guys,
I have a problem with mailbox that is located in on-premise Exchange 2019. I'm using hybrid mode with 99% mailboxes located in EXO. Let's name this mailbox: "Mailbox1".
Mailbox1 have 4 SMTP addresses. 3 of them are working correctly, only 1 is not working- mails sent on this SMTP are not delivered with error:
: 550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient XXXXXXXXX not found by SMTP address lookup
While I'm sending mail from this specific SMTP mail is delivered correctly - reply on this message is also not delivered.
I have found some discussions that could be related to this issue. For example:
All my accepted domains in EXO are configured as Authoritative. But I'm not sure that this is the root cause of this issue because it's working with 3 others SMTP for same mailbox and also some other mailboxes from on-premise are working correctly(some- not, same issue as described).
Do you have any experience with issue similar to this one?
BR,
Zakon
Jan 27 2023 02:34 AM
Jan 27 2023 04:50 PM
Jan 28 2023 01:29 AM
Jan 30 2023 03:50 PM
Feb 07 2023 04:07 PM - edited Feb 07 2023 04:09 PM
The bounce back is returned when the recipient address isn't available on the server where your MX is pointing to.
Please confirm if the 4 SMTP addresses on Mailbox 1 are of the same domain name.
Please confirm if there are other working mailboxes (Mailbox 2, mailbox 3) with address like the affected domain name on Mailbox 1
I look forward to your response in order to advise further.