Unable to send emails from shared mailbox

Question

I have setup a shared mailbox in Teams & Groups on MS 365 Admin Centre and added the relevant members to the shared mailbox and they all have Read, Manage and Send permissions but when I try to send an email from the mailbox I get the follow email message:

Your message did not reach some or all of the intended recipients.

  Subject:	test  
  Sent:	16/06/2022 13:24  

The following recipient(s) cannot be reached:
``` Garry Barton (SHHS) on 16/06/2022 13:24
This message could not be sent. You do not have the permission to send the message on behalf of the specified user.

__________________________________________________    
    
Diagnostic information for administrators:    
__________________________________________________    
    
Error is [0x80070005-0x000004dc-0x00000524].    
    
Exchange response headers:  
request-id:   
X-ServerApplication: Exchange/15.20.5353.014  
X-FEServer: LO3P123CA0003  
X-BEServer: CWLP265MB2707  
X-CalculatedBETarget: CWLP265MB2707.GBRP265.PROD.OUTLOOK.COM  
X-RequestId:   
X-ClientInfo:   
X-ElapsedTime: 62  
X-BackEndHttpStatus: 200  
X-ResponseCode: 0  
X-DiagInfo: CWLP265MB2707  
X-RequestType: Execute  


__________________________________________________    
    
ROPs Summary:    
    ```
0: ropSetProps (10) Processed(1) Completed(0)  
	ROP result: 0  
	Response codes: 0  
1: ropSetProps (10) Processed(1) Completed(0)  
	ROP result: 0  
	Response codes: 0  
2: ropFlushRecipients (14) Processed(1) Completed(0)  
	ROP result: 0  
	Response codes: 0  
3: ropSetProps (10) Processed(1) Completed(0)  
	ROP result: 0  
	Response codes: 0  
4: ropTransportSend (74) Processed(1) Completed(0)  
	ROP result: 0  
	Response codes: 1244  

---

Response Exceptions:

ROP Index: 4
ROP Associated: ropTransportSend (74)
Microsoft.Exchange.Data.Storage.SendAsDeniedException: Can't send message. ---> Microsoft.Mapi.MapiExceptionSendAsDenied: MapiExceptionSendAsDenied: Unable to send message. (hr=0x80070005, ec=1244)
0. 35250:0C000000, 1.36674:01000000, 1.61250:00000000, 1.45378:02000000, 1.44866:00000000, 1.36674:01000000, 1.61250:00000000, 1.45378:05000000, 1.44866:00000000, 1.36674:7A000000, 1.61250:00000000, 1.45378:08000000, 1.44866:00140000, 1.36674:0A000000, 1.61250:00000000, 1.45378:19000000, 1.44866:6E0D0000, 1.36674:0E000000, 1.61250:00000000, 1.45378:8A0D0000, 1.44866:78020000, 16.55847:4B0B0000, 17.43559:0000000034020000000000000000000000000000, 20.52176:140FE9940E00000000000000, 20.50032:140FE9947E1770200201DA36, 0.35180:01000000, 255.23226:8E000000, 255.27962:7A000000, 255.27962:0A000000, 255.27962:0E000000, 255.31418:0A002F3D, 0.35250:1A000000, 1.36674:0A000000, 1.61250:00000000, 1.45378:02000000, 1.44866:18000000, 1.36674:4A000000, 1.61250:00000000, 1.45378:1D000000, 1.44866:00000000, 16.55847:7E000000, 17.43559:0000000080030000000000000000000000000000, 20.52176:140FE9940E0070200A004366, 20.50032:140FE9947E171010C1000000, 0.35180:1F000430, 255.23226:01000000, 255.27962:0A000000, 255.27962:4A000000, 255.17082:DC040000, 0.44949:C9000000, 4.21921:DC040000, 255.27962:FA000000, 255.1494:CE000000, 0.38698:05000780, 1.41134:46000000, 7.36354:010000000000010B86000000, 0.37692:01000000, 0.37948:1A010480, 5.33852:00000000534D545000010480, 4.56248:DC040000, 7.40748:010000000000010B05000780, 7.57132:000000000000000000000000, 4.39640:DC040000, 1.63016:4A000000, 8.45434:D5014BE3351EAD4494FEB483C2C4C3971A010480, 1.46798:13000000, 5.10786:0000000031352E32302E353335332E3031343A43574C503236354D42323730373A39393530613839392D343561352D343838302D396536622D6663363364653136626233343A383335303000, 7.51330:B358220F934FDA082D666336, 0.39570:36626233, 1.55954:0A000000, 0.49266:A4000000, 1.33010:0A000000, 2.54258:00000000, 0.40002:7A000000, 1.56562:00000000, 1.64146:4A000000, 1.33010:4A000000, 2.54258:DC040000, 255.1750:11010000, 255.31418:0A001870, 0.22753:00000000, 255.21817:DC040000, 0.34722:40000A67, 4.51106:DC040000, 0.41890:1B010000, 4.58274:DC040000, 0.59285:00000000, 4.46997:DC040000
at Microsoft.Mapi.MapiExceptionHelper.InternalThrowIfErrorOrWarning(String message, Int32 hresult, Boolean allowWarnings, Int32 ec, DiagnosticContext diagCtx, Exception innerException, MapiStore mapiStore)
at Microsoft.Mapi.MapiExceptionHelper.ThrowIfError(String message, Int32 hresult, IExInterface iUnknown, Exception innerException, MapiStore mapiStore)
at Microsoft.Mapi.MapiBase.ThrowIfError(String message, Int32 hr)
at Microsoft.Mapi.MapiMessage.TransportSendMessage(PropValue[]& propsToReturn)
at Microsoft.Exchange.Data.StoreObjects.MapiAccessorExtensionMethods.TransportSendMessage(IStoreSession storeSession, Object mapiObject, ExTimeZone timezone, PropValue[]& mapiPropValues)
--- End of inner exception stack trace ---
at Microsoft.Exchange.Data.StoreObjects.MapiAccessorExtensionMethods.TransportSendMessage(IStoreSession storeSession, Object mapiObject, ExTimeZone timezone, PropValue[]& mapiPropValues)
at Microsoft.Exchange.Data.Storage.CoreItem.TransportSend(PropertyDefinition[]& properties, Object[]& values)
at Microsoft.Exchange.Data.StoreObjects.CoreItemMetricLogger.TransportSend(PropertyDefinition[]& properties, Object[]& values)
at Microsoft.Exchange.RpcClientAccess.Handler.Message.TransportSend()
at Microsoft.Exchange.RpcClientAccess.Handler.RopHandler.<>c__DisplayClass156_0.<TransportSend>b__0()
at Microsoft.Exchange.RpcClientAccess.Handler.ExceptionTranslator.TryExecuteCatchAndTranslateExceptions[TResult]

Transport-Send failed: failure enum(25), HResult(0x00000000), EC(1244).
Transport-Send failed: failure enum(22), HResult(0x00000000), EC(1244).
Submit-Message failed: message id(2), failure enum(13), HResult(0x80070005), EC(1244).

Does anyone have any suggestions of how this can be rectified??

Best Regards
Simon

Answer 1

Here it worked after downloading the address book.

File > Account Settings > Download Address Book.

Answer 2

We had this issue as well. The problem was that we'd created new Address Book Policies, which didn't include our shared mailboxes. It turns out that Outlook needs to be able to "see" the shared mailbox - OWA does not.

Everything worked again when I recreated the ABPs to include an Address List with the shared mailboxes. If you do this, don't forget to "tickle" the mailboxes:

Get-mailbox  -ResultSize 'Unlimited' | ForEach-Object {Set-Mailbox -Identity $.UserPrincipalName -SimpleDisplayName $.SimpleDisplayName -ErrorAction 'Stop'}

Then force a redownload of your Address Book in Outlook, and you should be able to send the email from a shared mailbox.

Answer 3

Hi @Geordie26 .

Have you tried to send email through OWA? If you haven’t, please try it and be free to feed back.

I’ve got the same error when I assign the permission to mailbox. After about 1 hour later, I would be able to send email from the shared mailbox.

According to my test, the issue may occur with it may take some time for changes to take effect in Outlook and OWA.

You could go to EAC and check if the user has been assigned send-as permissions.

If the issue still persist, please add the shared mailbox in outlook and try to send email again.
https://support.microsoft.com/en-us/office/open-and-use-a-shared-mailbox-in-outlook-d94a8e9e-21f1-4240-808b-de9c9c088afd

---

If the response is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 4

The issue was resolved (with Microsoft support help) by re-applying Full Access permissions, removing shared mailbox Outlook auto-mapping for the affected users, and then adding the shared mailbox manually in Outlook. Re-applying permission via the Office 365 admin centre didn't have any effect.

Detail steps - https://www.mysysadmintips.com/windows/clients/846-office-365-cannot-send-as-shared-mailboxes-from-outlook

Answer 5

Got this error after converting a user mailbox to a shared mailbox while MFA was set on the user. It looks like the MFA flag was stil set on the user account after conversion.

Removed MFA of the user account belonging to the shared mailbox and the problem was solved.