Account invitations are exactly what they sound like. They are the mechanism by which you can invite someone to create an account on your Callimachus instance. To invite a user navigate to the group to which you want them to belong (groups are found in /auth/groups/), select the "Edit" tab, and click the icon next to "Members". This will pop-up a dialog box for you to fill out with relevant information about the new user.

When a user is invited they will be able to create an account with whatever authentication options you have made available on your instance. 

A user MUST accept an invitation (follow the link in the email sent) before they are granted any permissions by the group.

Resend Invitations

Sometimes people forget to check their email or an invitation is filed into the spam folder and lost forever. That's why Callimachus offers the ability to resend an existing invitation. Rather than having to delete the old account and create a new one, you can just resend an invitation to the person reminding them to create an account. To do this, navigate to the user's account page in /auth/invited-users/ and click the Main Menu in the upper right and select "Re-send invitation". 

At any time you can check the /auth/invited-users/ directory to see which users have been invited but have not yet created an account. This is an easy way to keep track of potential and actual users of your Callimachus instance. 

Revoke Invitations

Invitations can be also be revoked, as well as resent. To revoke an invitation, navigate to the invited user's account page in /auth/invited-users/ and click the "Edit" tab. At the bottom of the edit tab you can click the red "Revoke invitation" button which will invalidate the pending invitation.