I was repeatedly getting “Sync Module failed to connect” error when creating a new system with a new Sync Module.

I was able to set it up by paying attention to:

• Only turn on 2.4GHz of home router WiFi. Most wireless routers today support both 2.4GHz and 5GHz bands, and they often share the same SSID. However, Blink Sync Module only supports 2.4GHz WiFi. During setup, your smart phone may send its current WiFi connection information, which is often just 5GHz WiFi channel and SSID (for higher bandwidth on the phone), to Sync Module. The Sync Module may fail to connect to your router. You can temporarily disable 5GHz part of your home router, add the Sync Module, and then turn on 5GHz in your router later.
• Check the WiFi password very carefully when entering on your smart phone to set up the Sync Module. The Blink app tends to lose the first character. Turn on “View the password” and double check the password that is entered.

After making sure both the above, I successfully added the Sync Module and created a new Blink system in my Blink app on phone. This allows me to add Blink cameras to the system.