Solved

I can't use the simulator/building that improves KERS

¿Qué has intentado hacer?
I tried to enter into the simulator and the building that improves KERS/DRS to start constructing those buildings

¿Qué es lo que ocurrió?
Nothing, it just doesn't acknowledge I'm trying to enter into the simulator menu

¿El problema ocurrió mientras usaba wi-fi, datos móviles o ambos?
Both

¿El error se produjo en la app, en PC o en ambos?
Both

¿Cuál es el modelo de su dispositivo?
Redmi Note 9 Pro

¿Qué sistema operativo posee?
Android

¿Cuál es el número de versión del sistema operativo?
The latest

¿Qué sistema operativo posee su PC?
Windows 10

¿En qué navegador ha experimentado el problema?
Chrome, android iGP app and windows desktop iGP app

¿Se puede reproducir el error?
I don't know if other people would be able to do it again but it happens always for me

Comentarios adicionales:

Yes, and that's the problem

I can't build them. The menu to build them isn't opening 

Oh, so I can't enter that menu when I have another construction going already? I knew I could only have one construction at a time but I didn't knew I had to end my current construction to enter the build menu

Thnaks