DVR Losing Series Recordings

[Jennifer1162]

Our DVR is failing to record programs after a series recording request has been entered.  Specifically, for example, we had a series recording set up for NBC Nightly News.  Recorded episodes for 2 nights and then disappeared.

At times when I attempt to set up the series recording again, I get an error message that the series is already entered, but none of the requests show up in the scheduled recordings queue.

Advice for a solution is appreciated.  Thanks.