I was having problems connecting to the Helix app, too. The Wi-Fi needs to be on the same network, and I had my VPN on, which prevented the Helix Stadium from being discovered by the app. I turned off my VPN, and all is good now.
Is there a way to make the parameter controller assignment per snapshot and not per preset? I want the expression pedal to control the amp drive in one snapshot without affecting it in the other snapshots. i.e., I want to assign EXP2 to the controller in Snapshot 1, but in my other snapshots, I want the controller to be "None".