This can occur if the user has not been invited to access NXT, or if the NXT invitation has expired.  Send a new invitation to the Raiser's Edge NXT.

If the user has been invited, and appears as Active but still receives this error:
  1. Locate the user in Control Panel > Security in Raiser's Edge NXT
  2. Click the three dots next to their account and select Disconnect accounts
  3. Send a new invitation for Raiser's Edge NXT
  4. Before the user accepts the invitation, have them clear their browser history and cache on their workstation
  5. Have the user accept the invitation
This could also occur if you have multiple accounts (multiple email addresses) and are not logged into with the address that was linked with the invitation.