Access Denied in New Outlook

This drove me crazy, and it was a simple fix, although by accident. Open edge, go to settings/history, and delete all time, every category. In my case the website was stored in a cookie, that cleared when I erased history. Cant promise it will work for you, but it did for me!

We're users of Microsoft 365 Business Standard. At the time of writing (February 2025), Microsoft is stepping up its attempts to "encourage" users to migrate from the "classic Outlook" email client which is part of the Office desktop suite to the "new Outlook" client which is a Webview2 app, that is to say little more than Outlook Web Access with a new skin. One of our users found she was being forced to run New Outlook. Aside from the numerous features of Classic Outlook which are not replicated in New Outlook (such as PST files), we experienced the further problem of being unable to run New Outlook, instead receiving the message "This account has been blocked from accessing the new Outlook for Windows by your system administrator."

Well, I'm the system administrator and I don't recall blocking anything, but I found a resolution as follows:

Log into Microsoft 365 with an administrator account. Launch Windows Powershell as Administrator.

Install the MS-Exchange library to Powershell with "Install-Module -Name ExchangeOnlineManagement -Scope CurrentUser". You may find you already have it, or you may get a message about the software being in an unstrusted repositry, in which case respond with a "Y".

Bring your MS-Exchange Powershell library up to date with "Update-Module -Name ExchangeOnlineManagement". These commands take a while to run, by the way; don't lose patience.

Connect to your Microsoft 365 Exchange Server from Powershell: (search "Connect to Exchange Online PowerShell" for the MS learn page) You may have to authenticate to MS 365 and grant yourself permission to use this stuff.

In Powershell type:

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline -UserPrincipalName {admin email address]

(Replace [admin email address] with your Microsoft 365 administrator email and Ignore all the messages your receive.)

You can then examine a user's OneWinNativeOutlookEnabled policy setting with:

Get-CASMailbox -Identity [user email address] | Format-List Name,OneWinNativeOutlookEnabled

If this is set to False the user's access to New Outlook will be blocked. Set it to True as follows:

Set-CASMailbox -Identity [user email address] -OneWinNativeOutlookEnabled $true

You can then run New Outlook, toggle it off, answer Microsoft's questionnaire as to why you don't want to switch to it, and go back to using Classic Outlook.

And you can hide the toggle with a policy setting, but that's another story.

See https://techcommunity.microsoft.com/blog/outlook/things-to-know-about-the-new-outlook-for-windows/3383964 for some more information

I cannot log on to microsoft outlook email, access denied?

Just chiming in to say this error is still happening-- it is happening to me right now. Like others, I will just switch back to the old Outlook because there does not appear to be any other way to resolve this.

i cannot access powerpoint and msword its says my subscription is expired so i try to update but its does not do anything