"Unable to Authorize the listed DLC"

[Cyrisal]

I was actually thinking about doing that myself, I had similar success with games which had issues, it was actually my next step, lets hope it works like it did for you mate. 

[Beldr-QAI]

I uninstalled origin and ME3, reinstalled in a new windows account and it worked... for 1 day. When I stoped playing and closed the game the dlc was unable to authorize once again.

[commanderd2006]

I've made zero changes to my computer since the last time I played Mass Effect 3 a year ago (no new hard drives, no operating system reinstalls, no renaming of the computer) and I'm getting the 'account invalid' error too. Do EA have a Helpline I can call? I'm happy enough to reinstall Origin and Mass Effect but if that doesn't work I'm a bit scuppered. (I've been playing a nostalgia run through Mass Effect and Mass Effect 2

[pawmajor]

Had the same problem last year.

Here is how I reslolved it:

1. Install the game and run it

2. Create another admin account on the system

3. Log to the new account and istal game

4. Launch and exit

5. In documents and settings find the ME3 folder and coppy all non save files to your original admin account (bio game if i remember correctly)

6. Enjoy the game

Rememember to disable the newly made account!