I tried to upload an ePub and throws me the following error:
Error ITMS-3000: "Line 75 column 29: element" data_file "incomplete, missing required element "checksum" at XPath / package / book / assets / asset  / data_file"
How I can fix it?
I solved this problem. The data provided in the upload process in itunes producer, should be similar to the OPF metadata.Simple. Ok.
Retrieving data ...