If a user hasn't accepted their invitation or their link has expired, you can resend the invitation from the Users page.
Resending a user invitation
Go to Users in the left sidebar.
Click the Invited tab.
Find the user and open their profile.
Click the three-dot menu in the top-right of their profile panel.
Select Resend invitation.
The user receives a new invitation email with a fresh activation link.
Invitation links expire after 24 hours. If a user says their link no longer works, resend the invitation rather than creating a new one.