U3000 Won't Connect to Phone Hot Spot

New U3000 after using Blackvue for a while.

I've successfully gone through the setup and connected the phone with the cam and registered the cam with the cloud. The latter was quite a pain as the car's android auto seemed to interfere with the process so had to register away from the car.

I can use the Thinkware app connection when connected with my home WiFi but it won't connect using my phone's hotspot. Password and Frequency are correct, and the phone shows as connected but the app says that connection fails. I also used my wife's phone with the same result. Both phones are Samsung S21 android 15.

Any ideas?