17

I have an email address like myname@company1.com and I want to access a shared mailbox sharedmailbox@company2.com, where company1 and company2 are just different names at the same server.

I use Thunderbird/Postbox client instead of Outlook due to important religious matters. And everything works fine if the shared mailbox is @company1.com. I only need to set:

User Name: myname@company1.com\sharedmailbox@company1.com

However, working with company2.com like this:

User Name: myname@company1.com\sharedmailbox@company2.com

does not work at all - the password is not accepted.

How can I work with Exchange's shared mailboxes if the domain names do not match?

Michal Czardybon
  • 426

2 Answers2

13

As per an answer listed on How to access a Shared Mailbox using Thunderbird or other IMAP client you may just need to define, confirm, or change a unique alias for the shared mailbox in Exchange 2016 and then use the below syntax rather than what you tried per your question.

User Name: myname@company1.com\sharedmailbox (user\shared mailbox alias)

How to access a Shared Mailbox using Thunderbird or other IMAP client

Exchange Configuration

USER EMAIL: user@maindomain.com   
PASSWORD: password
SHARED MAILBOX: shared@anotherdomain.com      (could also be @domain.com, of course)   
SHARED MAILBOX ALIAS: shared-mailbox

Note: Please make sure to create the UNIQUE alias always with the mailbox, because it creates the user [alias]@maindomain.com. In this case shared-mailbox@maindomain.com

Settings for IMAP Configuration

EMAIL ADDRESS: shared@anotherdomain.com (shared mailbox)
IMAP SERVER: outlook.office365.com   
SMTP SERVER: smtp.office365.com
USERNAME: user@maindomain.com\shared-mailbox  (user\shared mailbox alias)   
PASSWORD: password (user's password)

SMTP Login Is Different

USERNAME: user@maindomain.com  (users email)   
PASSWORD: password (user's password)

source

Vomit IT - Chunky Mess Style
  • 42,624
5

Just came across this a couple of years later, where the accepted answer did not work for me.

This works with Thunderbird 102.2.2 (IMAP configuration), given that you have permission(*) to access the shared mailbox with your account, say johndoe@example.com:

  • Username: mysharedmailbox@example.com
  • Security: SSL/TLS with OAuth2
    (This is enforced by Microsoft anyway).

Once saved, you'll be prompted with the Microsoft login window.

  • Select "Sign in with another account"
  • Login as johndoe@example.com with your usual password.

(*) Exchange admin center - (the shared mailbox) - Delegate

wolfmanx
  • 103
jp-jee
  • 171