Hosted Exchange Mailbox Configuration

E-mails
1

Hello

We are trying to configure our Hosted Exchange mailbox with Outlook but it isn’t working. Are there any special settings for this mailbox?

Thank you for your replies.

Best regards,

Loic

2

Hi @MairieS5

Which email client are you using?

Take a look at this guide :backhand_index_pointing_down:

https://docs.ovhcloud.com/fr/guides/web-cloud/email-and-collaborative-solutions/microsoft-exchange/how-to-configure-outlook-2016

Let me know, cheers.
Sergio Turpín

3

Good evening Sergio

Thank you for your reply. We are on EXCHANGE, I watched the video and did it but it does not connect, server refused. Do we need an Outlook license? And can the password contain special characters?

Have a good evening

Loic

4

Hi @MairieS5

No, you don’t need a special Outlook license to connect to an OVHcloud Hosted Exchange. You can use Outlook Classic at no extra cost.

Has your domain or account ever been associated with Office 365?

Let me know, cheers :wink:
Sergio Turpín

5

Hello Sergio

Thanks for your reply

No, I don’t think the domain or the account is associated with Office 365

Have a good day

Loic

6

Hi @MairieS5

I was mentioning this because if your domain or account has ever been associated with Office 365, Outlook will remember that and will constantly redirect to Microsoft, ignoring the OVHcloud Exchange server. I think that’s why you see a server rejection, since Microsoft doesn’t have your account.

Have you checked in the Associated domains section that the diagnosis of your domain is green, especially the SRV record that enables automatic configuration?

If you’ve checked this and it’s OK, give me feedback because I’ll tell you how to add an ExcludeExplicitO365Endpoint to your Windows registry.

Let me know, cheers.
Sergio Turpín

7

Thank you Sergio

Yes the domain is correctly associated (See screenshot)

Screenshot 2026-07-28 113240
Screenshot 2026-07-28 1132401217×370 25.3 KB

8

Thanks for the screenshot :+1:

Let's try the following:

  1. Open the Registry Editor (regedit) on your computer.
  2. Navigate to the following path:
    HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
  3. If the AutoDiscover folder does not exist, you can create it.
  4. Right‑click in the right pane and select New > DWORD (32‑bit) Value.
  5. Name the new value ExcludeExplicitO365Endpoint
  6. Double‑click it and set the value to 1

Let me know, cheers.
Sergio Turpín

9

Thanks for your instructions but it still doesn’t work

Here is the error code

Capture d’écran 2026-07-28 165014

10

Hello @MairieS5

Sometimes Windows stores an old password in the Credential Manager and Outlook gets confused. Go to the Control Panel, open “Credential Manager” and then “Windows Credentials”. Look for any entry that references your email address, Outlook or MicrosoftOffice and delete it. It’s a common cause of authentication failures :smirking_face:

Add the account again in Outlook Classic :right_arrow: Make sure you’re using the Outlook Classic version (the one that comes with Office, not the Windows 11 one). When adding the account, at the step where you enter the email, click “Advanced options” and check the box “Let me set up my account manually”. Then select “Exchange” as the account type.

Finally check the registry and restart. Make sure the ExcludeExplicitO365Endpoint registry key you added is still there and set to 1. Afterwards, close Outlook completely and restart the computer so all changes take effect.

Let me know, cheers :wink:
Sergio Turpín

11

Good evening, I'm interested in this topic. I'm on Exchange OVH or professional email Mai OVHl, and I'd like to reset the DNS without losing my emails. If anyone can help me, sincerely, Thibaut.

12

Hi @thible

Take a look at this documentation :backhand_index_pointing_up: and if you have any questions, let us know.

Kind regards,
Sergio Turpín

13

Hello Sergio

Sorry for the late reply, I'll look into it and keep you informed.

Best regards

Loic