I could be that in your nibe the tcp/ip modbus is set to “readonly”. Then that would indeed not work.
I’ve connected my S2125 via @Jan_Sparud 's fork of the app, but I was wondering if it is in any way possible to choose which entities I want to see. When I open the app now, it shows me a screen for a pool and I do not have a pool. Is it possible to choose which values I see and use them to calculate, for example, COP and monthly/yearly usage and production?