Classify Sequence using a Trained LSTM network - Error

Hi eveybody. I cannot solve this error :

Error using nnet.internal.cnn.util.NetworkDataValidator/assertValidSequenceInput (line 339)

Invalid prediction data. Predictors must be a N-by-1 cell array of sequences, where N is the number of sequences. All sequences must have

the same feature dimension and at least one time step.

I used already the same network and it work definitly fine. Now I have just loaded the trained network, and when I am trying to classify I get this error. I have tried already to convert the 2x2048 array in a cell but the error still appear. Any suggestion?

Thanks