Problème connexion compte O365 Outlook

Benjamin GENETELLI 0 Reputation points
2025-02-12T15:47:26.2766667+00:00

Bonjour,

J'ai un problème chez un client où nous avons fait une migration Exchange Server 2010 vers Office 365 dernièrement et il s'avère que depuis quelques jours j'ai 3-4 personnes qui peuvent plus ouvrir leur Outlook avec l'erreur suivante :

error1

J'ai donc fait un test de connectivité depuis le site : https://testconnectivity.microsoft.com/ et voici le résultat que j'ai obtenu :

testconnectivitycallays

J'ai fais ce même test de connectivity sur un autre utilisateur qui n'a pas problème particulier et évidemment tout est au vert, ces 2 utilisateurs sont sur le même tenant, la même OU, tout me parait identique à première vue.

Auriez-vous une piste surcomment je peux résoudre ce problème qui commence à être bloquant ?

En attente de vos retour,

Merci par avance.

Microsoft 365
Microsoft 365
Formerly Office 365, is a line of subscription services offered by Microsoft which adds to and includes the Microsoft Office product line.
5,768 questions
Exchange Server
Exchange Server
A family of Microsoft client/server messaging and collaboration software.
1,448 questions
Outlook
Outlook
A family of Microsoft email and calendar products.
4,505 questions
Windows 365 Business
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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2 answers

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  1. Alex Zhang-MSFT 6,230 Reputation points Microsoft External Staff
    2025-02-13T02:36:56.38+00:00

    Hello, @Benjamin GENETELLI,

    Welcome to the Microsoft Q&A platform!

    Since your question was posted in the Microsoft English forum, I will answer it in English, so please understand the inconvenience caused.

    Here's a combined approach to tackle the issue:

    1. Confirm Autodiscover and DNS Records: Start by ensuring that Autodiscover and DNS records are correctly pointing to Office 365 and not still referencing the old Exchange 2010 server. This is crucial for proper connectivity.
    2. Clear Autodiscover Cache: Sometimes, Outlook caches the pre-migration Autodiscover server, causing connection issues. You can clear this cache by setting the ExcludeLastKnownGoodUrl registry key:
      • Open the Registry Editor.
      • Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\<x.0>\Outlook\Autodiscover (replace <x.0> with your Office version, e.g., 14.0 for Office 2010).
      • Create a new DWORD value named ExcludeLastKnownGoodUrl and set it to 1.
    3. Recreate or Clear Outlook Profiles: Recreate or clear the affected users' Outlook profiles to update cached settings:
      • Exit Outlook.
      • Open Control Panel and select Mail.
      • Click Show Profiles and then Add to create a new profile.
      • Follow the wizard to add the email account and set the new profile as the default.
    4. Update Clients and Network Configuration: Ensure all clients have the latest updates and proper network configuration. This includes verifying that the network settings are correctly configured for Office 365.
    5. Hybrid Configuration: If you're in a hybrid environment, ensure that the Autodiscover record points to the on-premises Exchange CAS server. Sometimes, running the Set-ClientAccessServer -Identity “CAS Name” -AutoDiscoverServiceInternalUri $NULL command on the on-premises Exchange server can help.

    For more information, please check this document: Outlook cannot connect or web services cannot work after migrated to Microsoft 365 - Outlook | Microsoft Learn.

    Should you need more help on this, you can feel free to post back. 


    If the answer is helpful, please click on “Accept answer” as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.

    Thank you for your support and understanding.

    Best Wishes,

    Alex Zhang

    0 comments No comments

  2. Sandbrand Gregory 0 Reputation points
    2025-02-26T19:42:34.5533333+00:00

    Bonjour,

    je rencontre exactement le même problème sur deux comptes utilisateurs de mon tenant 365. Le problème disparaît et revient environ toutes les 48 heures,,je deviens fou et le support ne semble pas le trouver de réponse

    je n’arrive même pas à comprendre la raison, c’est complètement fou.


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