Exchange Hosting Service – Outlook Access Issue

There are no issues with our on-premises Exchange servers. The behavior users are seeing is caused by authorization problems that occur when Outlook tries to connect directly to Microsoft instead of our internal servers. Some changes on local machines are needed so Outlook checks our internal environment first and doesn’t bypass it by reaching Microsoft 365.

To correct this, a registry entry must be added to stop Outlook from detecting Office 365. Please be careful when editing the Registry, as incorrect changes can affect system stability.

You can apply the change through PowerShell:

Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Outlook\AutoDiscover" -Name 'ExcludeExplicitO365Endpoint' -Value 1 -Type DWORD -Force

Restart the computer after running the command. Registry changes do not take effect until the system is restarted. Create a new Outlook Profile by going to the control panel. It should not see the Office365 mailboxes anymore.

If you encounter any further issues, please don’t hesitate to contact our support team.

There are no issues with our on-premises Exchange servers. The behavior users are seeing is caused by authorization problems that occur when Outlook tries to connect directly to Microsoft instead of our internal servers. Some changes on local machines are needed so Outlook checks our internal environment first and doesn’t bypass it by reaching Microsoft 365.

To correct this, a registry entry must be added to stop Outlook from detecting Office 365. Please be careful when editing the Registry, as incorrect changes can affect system stability.

You can apply the change through PowerShell:

Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Outlook\AutoDiscover" -Name 'ExcludeExplicitO365Endpoint' -Value 1 -Type DWORD -Force

Restart the computer after running the command. Registry changes do not take effect until the system is restarted. Create a new Outlook Profile by going to the control panel. It should not see the Office365 mailboxes anymore.

If you encounter any further issues, please don’t hesitate to contact our support team.

We are aware of an issue currently affecting some users on mail.premium.exchange, where Outlook may display an error.

"Your mailbox has been temporarily moved on Microsoft Exchange Server. A temporary mailbox exists, but might not have all of your previous data. You can connect to the temporary mailbox or work offline with all of your old data. If you choose to work with your old data, you cannot send or receive email messages"

Affected users may experience synchronization problems, incorrect email address display in account settings, or issues adding multiple email accounts in Outlook. While a temporary mailbox may appear, it may not contain all previous data.

Our Team is actively investigating this issue and working to restore full functionality as a priority. We appreciate your patience and will provide updates as soon as possible.