Why I cant add new email account in new outlook but in old it works?

If you have the extra mailboxes you wish to add are part of the same company you could use permissions to add them to outlook.

I know one issue with permission-based mailboxes such as shared mailboxes is that they don’t work the same way in Outlook when compared to a full mailbox but a work around for this would be to apply the permissions via power shell and is the auto mapping option is turned off.

This will mean you would have to add the account to Outlook manually just like adding a full mailbox, the only difference is when it prompts for the user password you can select the option to sign in with another account and then use your main mailboxes log in information.

The Permission based mailbox is now set up to work the same way as a standard mailbox in Outlook with its own OST file and it uses your Office application license.

This method also helps with 2FA set up for generic email addresses and not all users will need to be added to the generic account 2FA as they will use their own account to access the mailbox.

If it would help here is a guide I set up for my staff on how to do permission based mailboxes via Power shell, Ir can only be done by 365 Admins

If you have never ran the PowerShell commands for Exchange from a PC you first have to install the Power Shell module by running the following command in PowerShell

Install-Module -Name ExchangeOnlineManagement

Click Y to all question

Now you need to set your user to allow scripts to run from Power Shell by running the following command

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Now you can connect to PowerShell using the commands below and next time you can skip this part

To connect PowerShell to your Office 365 Email Exchange:

Open Powershell (Run as an admin)

Type the following commands

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline

It will then prompt for 365 admin log in details

To add a user without auto mapping use the following command changing the (MailboxIdentity) to the mailbox address and the (UserIdentity) to the user who you want to access the mailbox, the brackets are not required.

Add-MailboxPermission -Identity (MailboxIdentity) -User (UserIdentity) -AccessRights FullAccess -AutoMapping $false

Look at the example below to see how it should be formated, the red and blue is just to make it easier to see what needs changing

In this example full access permissions are added to Kathleen mailbox with automapping disabled for the admin account.
So admin@ has full access to view all of Kathleens emails but wont add to Outlook by itself.

*Add-MailboxPermission -Identity ******@contoso.onmicrosoft.com -User *****@contoso.onmicrosoft.com -AccessRights FullAccess -AutoMapping $false

The power shell will display the following to show it has worked

Identity             User                                                       AccessRights                 IsInherited           Deny
--------               ----                                                        -----------                     -----------             ----
KathleenR        (DCServer)(AdminSAMAccountName)        {FullAccess}                       False              False

Repeat the previous steps for every mailbox where the user has full access permission and you want to disable automapping for the mailbox

If the users had auto mapping permissions then remove them via the web UI befor adding them via power shell again.

Once the permissions have been added it will show in the web UI against the full access permissions but only power shell can tell you if it has auto mapping enabled or disabled

There’s several responses that indicate that it is a Microsoft decision not to allow certain low cost 365 business accounts access to the new version of Outlook, at this time.

This is potentially going to change at some time in the future but for now there is no solution that will work for everyone until Microsoft changes its policy

Friends.

What you experience in the new Outlook is the result of Microsoft's new license requirements, which is a disaster for many.
Everything works in old Outlook - but not in new Outlook. Those of you who got it working have probably just been lucky.

Exchange accounts are not supported free of charge in the new Outlook.

https://m365maps.com/matrix.htm

Read my chat here:

https://answers.microsoft.com/en-us/outlook_com/forum/all/new-outlook-and-licenses-very-baffling/0a2101ff-46a4-4f51-9f6a-120f4d1745a6

Do you think it needs to be changed?

Vote up the proposal on this page:

https://feedbackportal.microsoft.com/feedback/idea/2f7925cb-3a80-ee11-a81c-000d3ae46fcb

To help keep us on track, let me summarize what we know:

The problem is not with customers, their laptops, or their company administrators. The problem is not with tenant settings.

The problem is with Microsoft.

Microsoft has made the conscious decision to prevent less-expensive Microsoft 365 licenses from using New Outlook for Windows. If you have an A1/E1/F1/Business Basic/EXO P1/EXO P2 or similar "low-cost' Microsoft 365 license, you will not be able to use it with New Outlook for Windows. Microsoft has officially confirmed that they've made this choice, and they have not provided any explanation as to why.

There are some anecdotal suggestions that some people have made it work. These can be grouped into three categories:

1. People who switched to New Outlook before Microsoft issued the restrictive update seem to be okay for now.
2. People who have copied one or more settings database files or registry entries from a working computer to a new computer can sometimes make it work.
3. People who purchase a more expensive license, then add their account to New Outlook, then downgrade that license, have in some cases reported success.

The reasons for these exceptions seem to be that - at the moment - New Outlook only checks the license when the account is first added to New Outlook. However, all of these workarounds seem unreliable (not everyone can make them work) and none of them are supported. Moreover, if Microsoft continues to pursue this destructive course, it's only a matter of time before they modify New Outlook to do a periodic license check, which will invalidate all of these workarounds and disconnect all of these users. But in ALL of these cases, if you remove the account from New Outlook, you will not be able to re-add it, and if you try to migrate to New Outlook from any other program with any of these licenses, they will not work, and if you buy new licenses for the inexpensive accounts, they will also not work. So these workarounds are not solutions in any real way, they're just some people finding a loophole for a specific case.

It is unfathomable to us why Microsoft is doing this, but we hope to get this reversed. But the only way we can get it reversed is if enough people complain. But it's critical to realize that Microsoft does not participate in this forum, and they are not seeing this thread. The only way to complain about this is to do it in the place where Microsoft actually pays attention, which is in their feedback portal.

To that end, we have created a master feedback item here: https://feedbackportal.microsoft.com/feedback/idea/2f7925cb-3a80-ee11-a81c-000d3ae46fcb . If you are upset about this issue - and you should be! - the best thing to do is to go to that link, and comment and upvote it. They read that feedback, and act on the highest upvote count and highest comment count items. That is the only way to get Microsoft's attention.

And don't stop there. Get your co-workers, get your company administrators, get everyone you know who is a Microsoft 365 customer to go to that same item and upvote it. If we could get many employees from just a few impacted companies to upvote and comment, we could get this on Microsoft's radar much more quickly. The issue is gaining more traction and attention as more people trip over this, but the more votes we can get, the faster the outcome will be.

All of the details of the issue are documented there so, please, if you're reading this, take a moment now to go upvote and comment so that we can get this insanity reversed as quickly as possible.

Thanks,

Glen

Yea, It's really weird. all my email addresses work on my desktop outlook and the windows mail, but the moment I switch over to the new "Window outlook", two of my email addresses no longer sink and I have no choice but the remove them from the new "window Outlook". The whole Idea of Outlook is to have a one stop shop. Now we are forced to toggle back and forth.