User with 2 mailboxes can only send files with one but not the other, when sending e-mails with attached files.

Question

Hello, I have a very strange issue.

One of my users has two mailboxes, both are not shared mailboxes, both are normal mailboxes, and the issue is that this user can only send e-mails with attached files with one of them but not the other, when she sends e-mail with attached files on her other e-mail, it simply goes to the Draft folder and stays there, she can send normal e-mails just fine with the "other" mailbox, but not with attached files.

And this is with the desktop application, again, sending attached files works with E-mail A, but not with E-mail B, so I can't possibly see this could be a issue with an Add-in? If it is an Add-in issue, shouldn't the problem hit both her mailboxes?

It's not a size issue either, she's set to be able to send E-mails as large as 35MB, she can't even send files less than 1MB, and it is all kinds of files with any extension.

User has full access to this Mailbox. So to make that clear, the user is not logged in to this other mailbox, but has it added as she has full access to it, I don't know if that makes any difference, but thought I would add this info too.

Answer 1

Hi @Josef Mouri ,

User has full access to this Mailbox. So to make that clear, the user is not logged in to this other mailbox, but has it added as she has full access to it

Is the mailbox (E-mail B) added automatically via automapping? If this is the case, I'd recommend trying to remove automapping of the mailbox, then add E-mail B as a secondary mailbox in the user's Outlook and check the result.

1. Run the command below to remove full access and then add it back with AutoMapping disabled:

   Remove-MailboxPermission -Identity <E-mail B> -User <E-mail A> -AccessRights FullAccess
   
   Add-MailboxPermission -Identity <E-mail B> -User <E-mail A> -AccessRights FullAccess -AutoMapping $false
   

2. Add E-mail B as an additional account in Outlook. Go to File > Add Account, type the email address of E-mail B, press the Connect button. When you are prompted to enter the credentials, input the account and password of E-mail A to pass the authentication. Detailed steps you can refer to How to add a shared mailbox as additional account in Outlook .
   (Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

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