Tips can be found here...
Downloading 'Additional Content' or the Logic Pro X app Tips
Take note in particular of the tips regarding Energy Saving settings and WiFi
The most common problems are usually related to Intranet (not Internet) issues (problems with your home network.. especially if you are using WiFi.. Try Ethernet instead if possible)
Some Internet providers limit the Max size of any one file when downloading... for certain groups of users... depending on what type of account/Package they have signed up for...(BT in the UK is a good example of this)
Issues with routing to and from Akamai Servers (The company Apple uses to store some of it's data on..) Solution is to try at a different time of day or night... or a different day altogether... This is often reported by European based users....
Issues with Non Apple Routers..... Not all routers are equal!
Conflicts with other applications running at the same time as the download in being done... Various types of adware can affect such things.. Check out Adwaremedic...
http://www.adwaremedic.com/index.php
Issues with their File system..... User accounts and so on....
Oddly enough many people have said ...
There is nothing wrong with my internet connection.
But frankly they wouldn't know if that were true or not because they base that opinion on routing to and from different locations... or the transfer of different types of files.. Just because they can download okay from other servers.. or their webpages load ok or they get email without an issue, often has no bearing on this issue at all...
and.. more often than not, in the end, it has been found it was issues with their Internet or Intranet or their Mac's File system/User account that was the root cause of the problem...
Read into that what you will....