Problems connecting to Tuya WiFi Smart Meter

In an effort to get my Apple app to pair with Home Assistant for the Tuya Wifi Smart Meter PJ 1103, for some reason in one house I can get the app to see the Meter and measure energy (yeah!), but in the house I want to measure energy in, it won’t, what on earth could the reason be? Its a completely standard wireless modem/router provided by the phone co Plusnet