You cannot connect two Office 365 accounts in one Outlook profile at the same time
Some customers find that if they try to configure two or
more Office 365 accounts in one Outlook profile, these accounts cannot all connect
to the Exchange Online Server at the same time, even though you have configured them correctly. For example, you have firstname.lastname@example.org (default account) and email@example.com configured, when firstname.lastname@example.org is connected to the server,
you cannot get email@example.com
This issue may occur intermittently.
To resolve this issue, use the Add-RecipientPermission cmdlet to add SendAs permission to the
default account. To do so, use the following steps:
- Connect Windows PowerShell to the Office 365
For detailed steps, visit Use
Windows PowerShell in Exchange Online .
2. Run the cmdlet that resembles the following.
Please be noted that firstname.lastname@example.org is
the default account in Outlook.
$target_giving = 'email@example.com'
$user_getting = 'firstname.lastname@example.org'
$target_giving -User $user_getting -AccessRights FullAccess -InheritanceType
Add-RecipientPermission $target_giving -Trustee $user_getting -AccessRights
Note: More details about Add-RecipientPermission
IF this method does not resolve this issue, welcome to leave a comment here, or follow up on the original post http://community.office365.com/en-us/f/160/t/3505.aspx .