May 2019
The way i fixed mine was to go into the "addin" files and under each of the dlc packages there is a manifest file that needs to be edited so that the "1" in RequiresAuthorization="1"> is actually RequiresAuthorization="0"> with a text editor. once you save each of the dlcs after doing this to each of them it should work.
November 2019
Can you please tell me exactly the name of the files that need to be updated???
December 2019
If you go into your DA2 folder then into the folder "addins" your DLC should be there. Go into each of those folders and open the "manifest" file with a text editor to change the numbers.
July 2021
I know this is old but lemme help those who stumble by looking for help:
BTW: I downloaded mine from here: https://help.ea.com/en-gb/help/faq/dlc-for-classic-games/
I'm not sure if this fix works in most cases but meh.
1. For authorised downloads, go into your "addins" files in you DA2 folder. There's a file called "manifest", open it using notepad.
Once open, press ctrl and f and search for the line "Mid=XXX" (number varies). delete ONLY this line. RIght next to it should be "RequiresAuthorization="1". Set the 1 to a 0.
Save and close.
2. If they are not showing up in game, make sure you are using the same email from that site ^ that you use ingame, otherwise,they won't work. (Don't ask me why, I think it's stupid)
Now, make sure the site is set to your country. Mine was set to Canada, so that may be the default.
Other then that, I can be of no help. I hope someone finds this useful tho \( ᵔ︠ ͜ʖ ︡ᵔ)/
July 2021