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Question

Hi All,

I have my environment on Exchange Online and users have Outlook version 2309 installed on their systems as shown in the image below:

Suddenly the users are facing the below error:

I have checked the certificate, and the certificate was showing as expired. However, I have renewed the certificate for the organization in M365 by adding domain DNS entries in the certificate provider.

Earlier the certificate used to get renewed by itself, but this is not the case this time.

How can I renew the certificate for all Outlook users?

Answer 1

Hi @Garima Das

According to the error prompt, is a common problem caused by certificates.

Please try manually deleting the following registry key to check if that helps.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\AuthRoot\Certificates

(Note: Serious problems can occur if you modify the registry incorrectly. Before making changes, back up the registry to restore it in case something goes wrong.)

In addition, this article details 3 common problem warnings about certificates, which you can refer to:

https://social.technet.microsoft.com/Forums/en-US/fa78799b-5c55-4c71-973b-0e186612ff6f/checklist-for-exchange-certificate-issues?forum=exchangesvrgeneral.

When a certificate is about to expired, we just need to renew it by referring the following article:

Renew an Exchange Certificate

https://learn.microsoft.com/en-us/exchange/architecture/client-access/renew-certificates?view=exchserver-2019

To avoid any conflictions, it’s recommended to remove the expired certificate from the certificate store.

Hope this helps!

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