I think I have created a shared mailbox for my non-profit, but I need advice please

Question

I have created (I think) a shared mailbox for a small registered charity in the UK and have 10 licences with my basic Microsoft account with onmicrosoft.com.

Aside from myself there are two other trustees who need access to the shared mailbox. I am the admin and have added licences and email addresses for each of us in addition to the shared mailbox. The other trustees are in different parts of the UK.

I have set up email accounts for each of us, but they can't see their accounts. One of the other trustees called me yesterday and went through the process to see her account and received a notification that the procedure to reset her password had not been authorised by the administrator (me). I have toggled on the Reset Password indicator on the admin portal, but this has made no difference.

A shared mailbox is all the Trust requires from onmicrosoft.

Answer 1

Hello @Catherine Howard

Based on your provided information, it looks like you are having an issue related to user is unable to access account. 

For this situation, could you please help me to reset user password by going to: 

1. Go to Microsoft 365 Admin center 
2. Open Users > Active Users and select the user that you want to reset the password 
3. Click on Reset Password and make sure to tick on the option "Require this user to change their password when they first log in"

From this page, you can also check if the account is blocked sign-in or not. If the account is blocked, please help me to unblock and ask the user try to sign in again. 

If the issue is not resolved, could you please let me know the error they are received when accessing to Office portal?

Additionally, please provide me more details about the shared mailbox issue (what is the error code or any issue when trying to open the shared mailbox). 

To know which type of mailbox, you can go to Exchange admin center > Extend Recipients and select Mailboxes 

For more details: Recipients in Exchange Online | Microsoft Learn

Please feel free to let me know if you have any update about this situation. 

Answer 2

For this scenario, the key points are:

1. A shared mailbox alone is not enough
   • Each trustee must have a licensed Exchange Online mailbox to access the shared mailbox.
   • The shared mailbox itself does not need its own license as long as it stays under 50 GB.
   • A Microsoft 365 Apps-only/basic subscription without Exchange Online is not sufficient; the plan must “include email (the Exchange Online service).”
2. Check subscription type
   • Ensure the tenant is using a Microsoft 365 for business plan that includes email (for example, Microsoft 365 Business Standard or any plan with Exchange Online).
   • If the current licenses are for Microsoft 365 Apps for business (apps only), users will not have mailboxes and therefore cannot access the shared mailbox.
3. How access to the shared mailbox should work
   • Create a normal user mailbox for each trustee (which requires a license that includes Exchange Online).
   • Create the shared mailbox for the charity.
   • As admin, assign the trustees as members of the shared mailbox (Full Access and Send As/Send on behalf, as needed).
   • Trustees then sign in with their own accounts and open the shared mailbox in Outlook (desktop, web, or mobile). They do not sign in directly to the shared mailbox.
4. Password reset issue
   • The “Reset password” toggle in the admin portal controls whether users can self-service reset their own passwords.
   • If trustees are seeing that password reset is not authorized, verify:
     • Their user accounts actually exist and are licensed with a plan that includes email.
     • The self-service password reset policy is correctly configured for those users.
5. If only a shared mailbox is needed
   • At minimum, one licensed user with an Exchange Online mailbox is required to administer and access the shared mailbox.
   • Additional trustees who need access must also have licensed mailboxes; access to a shared mailbox is always via each person’s own mailbox.

In practice, confirm that the 10 licenses in the tenant are a Microsoft 365 for business plan that includes Exchange Online, assign those to the three trustee accounts, then assign those accounts as members of the shared mailbox and have them open it from their own Outlook profiles.

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References:

• About shared mailboxes in Microsoft 365
• About shared mailboxes, shared folders, and shared calendars in Outlook
• Give mailbox permissions to another Microsoft 365 user - Admin help
• M365E5 - Mailboxes management - Microsoft Q&A
• License restoration - Microsoft Q&A
• No license associated with my email account - Microsoft Q&A