Use checkArgsF​orHandleTo​Print error ，The input parameter of the handle contains non-handle values.

I run a Re-ID code,when i run the train code,and it has run the dataset,it has an error in epoch2 and it doesn't draw the results。But when it run the epoch1，everything is goning well. Error is as follows

    % Use checkArgsForHandleToPrint error
The input parameter of the handle contains non-handle values.
error in  checkArgsForHandleToPrint
error in print>LocalCreatePrintJob (line 216)
    handles = checkArgsForHandleToPrint(0, varargin{:});
error in print (line 38)
    [pj, inputargs] = LocalCreatePrintJob(varargin{:});
error in cnn_train_dag (line 139)
    print(1, modelFigPath, '-dpdf') ;
error in train_id_net_res_2stream (line 34)
[net,info] = cnn_train_dag(net, imdb, @getBatch,opts) ;

I would appreciate it if someone would help me.