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Outlook changes connected Exchange server to outlook.com from Exchange services host

Pfaffie 0 Reputation points
2025-12-11T09:10:24.6866667+00:00
  • new behavior injected itself after 3+ years of successfully connecting to exchange.ionos.com account

Outlook Exchange connected account suddenly, and automatically, changed from ionos.com hosted Exchange account to an outlook.com account

  • created a new Outlook mail profile and successfully connected to exchange.ionos.com private domain email account via an Exchange connection setup, outlook successfully connects and downloads until Outlook app auto-logs me into my 365 account, at which time the email account auto-changes to the outlook.com account breaking my connection to my ionos.com hosted account
  • the autodiscover.xml file shows the correct connection to the exchange.ionos.com domain / account after setup, until the auto-change to outlook.com
  • removed all autodiscover.xml files and tried again, ...successful until Outlook app logged me into 365 account
  • added ExcludeHttpsRootDomain registry setting, problem persists with many attempts... to include deleting autodiscover registry entries pointing to hotmail.com, outlook.com, etc...
  • the 'Access this account from the web' url under the account changes to reflect the outlook.com url from the exchange.ionos.com link

I have another personal ionos.com Exchange Outlook connection on a different Windows box and have not experienced the same issue.

Looking for the solution to this odd behavior, thanks in advance

Outlook | Windows | Classic Outlook for Windows | For home

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  1. Q&A Assist
    2025-12-11T09:10:39.34+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    It seems that you are experiencing issues with Outlook automatically switching your connected Exchange account from your ionos.com hosted Exchange account to an outlook.com account. This behavior may be related to Autodiscover settings or how Outlook handles account connections.

    Here are some steps you can take to troubleshoot and potentially resolve the issue:

    1. Check Autodiscover Configuration: Ensure that the Autodiscover service is correctly configured for your ionos.com account. You mentioned that the autodiscover.xml file shows the correct connection initially, but it may be worth verifying that there are no conflicting settings in your DNS or Autodiscover configuration.
    2. Disable Connected Experiences: If you want to prevent Outlook from automatically logging into your Microsoft 365 account, you can disable connected experiences in Office. This can be done through Group Policy Management Editor by navigating to Administrative Templates > Microsoft Office 2016 > Privacy > Trust Center and enabling the policy for connected experiences.
    3. Registry Settings: You mentioned adding the ExcludeHttpsRootDomain registry setting, which is a good step. Make sure that other related registry settings are also configured correctly. Sometimes, clearing out old or conflicting registry entries related to Autodiscover can help.
    4. Create a New Profile: Since you have already created a new Outlook profile, ensure that you are not inadvertently linking your ionos.com account with your Microsoft 365 account during the setup process. When setting up your account, ensure that you are selecting the correct account type and server settings.
    5. Contact Support: If the issue persists, consider reaching out to IONOS support or Microsoft support for further assistance, as they may have specific insights or tools to diagnose the problem.

    These steps may help you maintain your connection to the ionos.com hosted Exchange account without it switching to outlook.com.

    References:

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