Which of the following is NOT a valid reason for dismissing a fair hearing request?

The selection of the choice indicating that a representative has not been authorized as a valid reason for dismissing a fair hearing request is correct because participation in a fair hearing typically requires that the representative has the proper authorization to act on behalf of the household. If a hearing officer cannot verify this authorization, it can undermine the integrity of the process and result in the dismissal of the request.

In contrast, the other reasons listed do not reflect valid grounds for dismissing the hearing request. For instance, if the hearing officer is unavailable, this issue can usually be resolved by rescheduling rather than dismissing the request outright. Additionally, if the household or the representative withdraws, that is a clear indication that they no longer wish to proceed, which respects their right to withdraw. Lastly, if the FNS (Food and Nutrition Services) unit fails to appear without good cause, this generally does not justify dismissing the request because the system is designed to ensure that the household's concerns are heard and addressed, regardless of one party’s absence.

So, in the context of fair hearing procedures, having a duly authorized representative is essential, and a failure to ensure that authorization exists can lead to proper dismissal of the hearing request.