A file cannot be downloaded more than 20 times within a 24-hour period. Once you reach this limit your item will be flagged and you will not be able to download the file for a further 24 hours.
Envato recommends against the use of download managers to download your purchased files from Envato Market.
Download managers send multiple requests and create multiple connections to the server - each one counting as a download.
The server will receive an abnormally large amount of requests to download the file(s) which may result in the item exceeding the download limit.