Outlook not sending to certain domains

Question

Outlook not sending to certain domains

Tumi Masemola 0

Good Day

I have a strange issue here. We have an on Premises Exchange Server 2019 and users on Office 2016, 2019 and 2022. Some users can't send emails to certain external domains, it brings out an error that the email address doesn't exist. But if they send to the same email address using their Phones or OWA, the email goes through and is received by the recipient.

Please help with some ideas here. Thank You.

Aholic Liang-MSFT 13,871 Reputation points Microsoft External Staff

2023-02-21T05:56:13.84+00:00

Hi @Tumi Masemola ，

In order to narrow down the issue, I would like to confirm the following information with you:

1. Is the external email address auto filled by the AutoComplete feature of Outlook client?

2. Or the external email address of your choice from the Offline Global Address List ?

If Andy’s suggestion was helpful, you can click the "Accept Answer" button under his post so that other's with similar question can benefit from this thread as well.

If you still have further questions or concerns, feel free to post back.
Aholic Liang-MSFT 13,871 Reputation points Microsoft External Staff

2023-02-28T05:16:48.9566667+00:00

Hi @Tumi Masemola ，

Does this issue have any updates?

If it has been resolved, please click "Accept as answer" to mark useful post or share your solution, your action would benefit others who have similar issues.

If you have any questions or need further assistance, please feel free to post back. Thanks!

1 answer

Your answer

Aholic Liang-MSFT 13,871 Reputation points Microsoft External Staff

2023-02-21T05:56:13.84+00:00

Hi @Tumi Masemola ，

In order to narrow down the issue, I would like to confirm the following information with you:

1. Is the external email address auto filled by the AutoComplete feature of Outlook client?

2. Or the external email address of your choice from the Offline Global Address List ?

If Andy’s suggestion was helpful, you can click the "Accept Answer" button under his post so that other's with similar question can benefit from this thread as well.

If you still have further questions or concerns, feel free to post back.
Aholic Liang-MSFT 13,871 Reputation points Microsoft External Staff

2023-02-28T05:16:48.9566667+00:00

Hi @Tumi Masemola ，

Does this issue have any updates?

If it has been resolved, please click "Accept as answer" to mark useful post or share your solution, your action would benefit others who have similar issues.

If you have any questions or need further assistance, please feel free to post back. Thanks!

Answer 1

Andy David - MVP 153.9K MVP

Sounds like cached entries in Outlook perhaps.

Consider testing with a user and deleting the cached entry in Outlook and re-sendind

https://learn.microsoft.com/en-us/outlook/troubleshoot/contacts/information-about-the-outlook-autocomplete-list#remove-autocomplete-list-entries-one-at-a-time

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Outlook not sending to certain domains

1 answer

Your answer