No input data found for 'Tutorial1_21.bnn'

Dear all,
I just downloaded my FLUKA and tried to run a tutorial file. As I process my data, I can’t creat my Tutorial1_21.bnn file. The output shows like:
WARNING: No input data found for ‘Tutorial1_21.bnn’
Error processing: Tutorial1_21.bnn
Ended: 2020.08.12 01:03:33

Possible errors: Tutorial1_21.bnn
Correctly processed:
and the status for Data is Error.
As I emerge to my USERBIN output, it shows like:

e> ERROR: Error loading USRBIN file
[Errno 2] No such file or directory: ‘/Users/gengqiaolei/FLUKA/Tutorial/Tutorial1_21.bnn’

What should I do?
Best regards,

Dear Charlie,

the reason could be that the simulation did not finish successfully. Please check the produced .out, .log and .err files if there was an error.