Well I can say once again after testing it again. It works fine with my psychical ME3 N7 Collectors Edition with all dlc (cause am insane) which of course is only works via Origin.
As to your issue. To say what is causing interferance could be a multitude of things ranging from games versions, mods, no cd/dvd cracks, PC Security programs, Anti Cheat program and lastly OS version.
My guess is that your problem is IE 10/11. When I did have that problem I went into the security settings for IE and added Cheathappens.com to the list of trusted websites. After I did that the problem went away.
Will that work for all instances of trainer failures due to having updated to IE 10/11? That sure sounds easier than having to roll back to IE 9 if that's so.
If you have IE10/11 installed what I suggested should do the trick.