If you're using 5D3, you need to select which memory card that you'd like to display, please select slot 2(SD Card) in camera menu.
After you select SD card to display, set the RATE button to "protect" so you can mark "protect" the photos on SD (not CF, or rate the photos on SD).
However, I've found that the default setting of Wi-Fi will upload photos to their server, then redirect to your target device, such as iPad or PC, it's quite slow for my environment. I disable the relay mode, buy another APP(Free eye-fi APP is not good enough for me), change the target to my Ipad in eye-fi setup software. Now, everything seem great, the photos can direct transfer to my ipad in Direct mode or under the same WiFi using 3th party APP. Somethings, the connection between iPad and eye-fi is dropped, I need to push the PLAY button on 5D3, reprotect a photo, after few second, the photo transfer again(you may need to reconnect the WiFi in iPad setting page).
Eye-fi is a great product, I can show the photos to my family on the fly. If I can change the target using my iPhone/ iPad, not the PC, it would be nice.