Having some downloading issues

I've been converting files into PDF's using the Acrobat website, compiling everything into their own folders then finally all of those folders go under one folder. When I try to download it to my Mac, I keep getting the "Download error, this folder may have been removed and cannot be downloaded." I try downloading one of the individual folders, that works but I can't download any of the other ones(getting the same error message). It's quite frustrating and would like any help thank you.