Shared MailBox SMTP Auth

Hi Özkan TOPAL,

From the Microsoft official article mentioned, shared mailbox is a type of user mailbox that doesn’t have its own user name and password. As a result, users can’t log into it them directly. You can refer this article: https://technet.microsoft.com/en-us/library/mt577278(v=exchg.160).aspx

So, if you have any concern/issue when you use shared mailbox to sign in Outlook on the web, Outlook client to send/receive emails directly, we can’t support it since it does conflict with the Microsoft official article reported. Meanwhile, as I mentioned, SMTP relay need a normal user mailbox (not a shared mailbox), you can refer above requirements for SMTP relay , so you can’t use shared mailbox to perform SMTP relay.

Thanks,

Richard

Hi Özkan TOPAL,

As we know, a shared mailbox is a mailbox that multiple users can use to read and send email messages (shared mailbox has no any license), and shared mailbox is a type of user mailbox that doesn’t have its own user name and password. As a result, users can’t log into it them directly. To access a shared mailbox, users must first be granted Send As or Full Access permissions to the mailbox. Once that’s done, users sign into their own mailboxes and then access the shared mailbox by adding it to their Outlook profile.

About you mentioned “Shared Mailbox also licensed with "Office 365 Enterprise E3"”, may I know if you converted this shared mailbox to user mailbox and assign it E3 license?

Meanwhile, based on your description, you want to use this “shared mailbox” as application mail sender, since shared mailbox has no password (authentication), so shared mailbox can’t use SMTP client submission to configure as application mail sender. You can see the requirements for SMTP client submission:

For more information about SMTP relay, please refer: https://support.office.com/en-us/article/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-office-365-69f58e99-c550-4274-ad18-c805d654b4c4. And please tell us what kind of SMTP relay do you use.

Thanks,

Richard

Hi,

Sorry for that, but you have some mistakes. First, when I've added a shared mailbox, it's also listed on "Active Users" with marked as "Unlicensed". I can assign license and set password for the "Shared Mailbox"s user. Also I have access to enable Email Apps for the user. "Shared Mailbox" is a user with mailbox, not group. I can login via;

Outlook on the web

Outlook desktop (MAPI)

Exchange web services

Mobile (Exchange ActiveSync)

IMAP

POP

All enabled for my all 3 shared mailboxes.

Thanks,

Hi,

Thank you for your reply. I'm also using Exchange Server 2013 and 2016, you're correct for them. But my question was for Office365 and Exchange Online. I've created "Shared Mailbox" from Office365 Admin Center and also Exchange Online Admin Center, both are listed on Office365 Admin Center Active Users list (signed as Unlicensed) and also Azure Active Directory Users list. So I can manage their password and login via Outlook Web.

you may check it from Shared Mailboxes "A few drawbacks:" section:

https://support.office.com/en-US/client/results?Shownav=true&lcid=1033&ns=O365ENTADMIN&version=15&omkt=en-US&ver=15&services=BPOS\_S\_TODO\_2%2cFORMS\_PLAN\_E3%2cSTREAM\_O365\_E3%2cDeskless%2cFLOW\_O365\_P2%2cPOWERAPPS\_O365\_P2%2cTEAMS1%2cPROJECTWORKMANAGEMENT%2cSWAY%2cINTUNE\_O365%2cYAMMER\_ENTERPRISE%2cRMS\_S\_ENTERPRISE%2cOFFICESUBSCRIPTION%2cMCOSTANDARD%2cSHAREPOINTWAC%2cSHAREPOINTENTERPRISE%2cEXCHANGE\_S\_ENTERPRISE&HelpID=O365E\_ESTypesofGroups

In benefits section there is a mention;

"You don't need to assign licenses to mailboxes that are under 50 GB.".

If I assign Exchange Online or ES3 license to "Shared Mailbox", that enables  Email Apps allowable.

Outlook on the web

Outlook desktop (MAPI)

Exchange web services

Mobile (Exchange ActiveSync)

IMAP

POP

I've tested for my 3 Shared "licensed" Mailboxes, all have Outlook Web, IMAP and POP connections. But SMTP AUTH is not possible. 

Thanks,