Entity not avaiable in REST API

I have created a new entity which is calculated by some other entities:

  - sensor:
       - name: "pv_total"
         unit_of_measurement: "W"
         state: "{{ states('sensor.solarnet_pv_leistung') | float  + states('sensor.carport_solarnet_pv_leistung_2') | float }}"

Now I would like to access this entity “pv_total” by REST API, but there is no value. Does I have to set some other options on the entity?

We can’t help debug a REST request if you don’t share what you’re actually doing.

Sorry for that, I was just stupid. Sensorname was wrong