Hi @mateusguilherme
Which version of the ArduinoJson library are you using?
5.0 or 6.0?
With ArduinoJson 5, you invoked the JSON parser by calling JsonBuffer::parseObject() or JsonBuffer::parseArray().
With ArduinoJson 6, you call the function deserializeJson() and pass the JsonDocument and the input as arguments.
RV mineirim