Recently i posted a Q about shared mailboxes - yesterday was able to successfully setup 4 different shared mailboxes using Exchange Powershell. Configured full access permissions for the appropriate users and all seemed to be ok but users today have advised me that they can't email those shared mailboxes internally. They get a bounce back message straightaway saying 'the email address you entered can't be found'
External emails are fine.
I'm guessing I haven't configured something else as well?