Excel/Outlook: how do you access multiple shared inboxes?

I've managed to retrieve mails from the shared inbox using the following code

   Sub GetFromOutlook()
    Dim OutlookApp As Outlook.Application
    Dim oaccount As Outlook.Account
    Dim OutlookNamespace As Namespace
    Dim ostore As Outlook.Store
    Dim Folder As MAPIFolder
    Dim OutlookMail As Variant
    Dim i As Integer   
    MailBoxName = "support@company.com"
    Set OutlookApp1 = New Outlook.Application
    Set OutlookNamespace = OutlookApp.GetNamespace("MAPI")

    Set objOwner = OutlookNamespace.CreateRecipient(accName)
    objOwner.Resolve

    If objOwner.Resolved Then
        Set Folder = OutlookNamespace.GetSharedDefaultFolder(objOwner, olFolderInbox).Folders("IL").Folders("5")

However, when I try to change the MailBoxName = "support@company.com" to "sales@company.com" later on in the code, I get the following error:

Run-time error -2147221219 (8004011d)
The operation failed because of a registry or installation problem. Restart Outlook andtry again.If the problem persists, reinstall.

It is if like Excel/Outlook remembers the connection. Can someone help with this problem?