In rare cases, Groove may be unable to send a message or invitation to one or more recipients. For example, Groove cannot send a message if its recipient list includes an e-mail contact.
To resolve this problem, send a new message or invitation to your recipient(s) and consider the following suggestions:
For messages, find a saved copy of the message in the Sent view of your Message History. You can forward the saved copy to create a new message. (You must create invitations from scratch; Groove does not save invitations after you send them.)
Ensure that instant messages do not include e-mail contacts as recipients. To send a message to an email contact, right-click the contact and select Send Message. This will open your e-mail client with a new message addressed to the email contact.