How do I report a broken file?

the file

S2A_OPER_PRD_MSIL1C_PDMC_20160804T002200_R110_V20160803T142112_20160803T142115

downloaded across PEPS is broken. It is only 1.5 Mb, and does not contains any band data.

It is absent on scihub.copernicus

Probably you need to ask the PEPS guys. Try exppeps@cnes.fr

See https://sentinel.esa.int/web/sentinel/news/-/article/sentinel-2-products-affected-by-anomaly-from-3-to-5-august-2016. There has been an issue on the SciHub. Some products were not consistent and have been removed from the SciHub. It should have been reprocessed and made available now (or will be soon if not yet).