Hi,
If on PFD there wasn't any indication to be on pause, then probably was a WASM crash. Pause at TOD will give you a message on PFD in red.
To unpause this aircraft just press "P" key.
And could be that the route calculations was putting you at TOD.
However if there was no indication of being pause at TOD (or 100nm from it) most likely scenario will be a WASM crash. You need to restart!
Miguel