Check the status of your local WiFi network to ensure your internet connection is online.
Move your Mini closer to the WiFi access point (i.e. your router) and attempt to connect it there, then move it back to its original location once connected.
Make sure that your phone is connected to the same signal as the one you are connecting your Mini to. For example, if you are connecting it to "My WiFi-2.4", verify your phone is connected to "My WiFi-2.4" before you attempt to add Mini in the app. Then, launch the app, and tap “+ Add a Diffuser.”
If you still receive an error when it is connecting to your WiFi, reboot your WiFi by unplugging your router (or your modem & router if they are separate) from power for 3 minutes, then plug it back in.
Once it has had time to boot back up completely, follow these steps to reset the diffuser and connect it to the app:
Press and hold the "+" and "-" buttons on your diffuser at the same time for 5 seconds, until the lights flash.
The lights will flash 3 more times, and turn back on.
Re-try the connection.
Note: Connecting your Aera Mini to a mesh WiFi system? Try creating a Guest network, and connect your Aera Mini to that network.