See to which country your 3DS is set to in the 3DS settings. Also the eShop should give you the to revert back to the region that was set to, or change to a new one (but the country has to be in NA for the NTSC region for example, etc)It was set to the U.S by default and I have changed it a few times to troubleshoot such as changing it to SG and UK but it gave me the same message, so I placed it back to the U.S. Does your IP factor in the error code? I don't have a U.S IP though.
The games were downloaded online as CIA files then installed with FBI.