ᐅ Heat Pump Problem – Supply Line Cold, No Hot Water: System Limitations

I have a problem with my heat pump.
We just bought the house, so I am not familiar with it yet.
The supply line is ice cold, so it is not heating. Hot water is not working either. It is controlled by a Dimplex heat pump manager. The display shows "System Limit. Lockout." Normally, it should say something like "Heat Pump On." What could this be? The problem has only appeared recently.

Regards,
Tobi

Have you checked the manual for the Dimplex? It contains a lot of information about different lockouts. However, without the exact model number, we can only guess.
Is the message on the display really just "System limit. Lockout."?

Yes. It says exactly that.
If I’m reading it correctly, the heating system is a Dimplex LA17TU and there is a Hydrotower HWK 332 Econ with a heat pump manager in the basement.
I will probably need to call the installer. I can’t find this information in the manual.

When I enter "Dimplex System Grenze Sperre" into Google, the first three search results already seem to offer quite competent explanations and solutions. Is there really nothing among them?

These are the manuals, but they do not contain any relevant information. Or do you get different search results?