Sorry, that user has already been invited. You may only invite a user to a topic once

[techAPJ (Arpit Jalan)]

@jtlindsey

On a new installation, this did not happen.

Few questions:

• are you admin on the forum you are inviting users? you need to be group owner or admin to invite user to a group.
• are the group automatic (shipped default by Discourse) or custom (created by you)?