Hi ali farid,
The error you are getting is related to the observation that you are passing to Agent A.
The cause of the error is indicated as: "Observation specification must be scalar if not created by bus2RLSpec".
This means that the observation specification must either be a scalar, or if it needs to be of bus type then, "bus2RLSpec" function must be used to convert the bus object to an RL specification object. I suppose that when you say that you have added two more scalars as observation along with the image you have used the bus creation block to do so. If it is the case then, you could try using the "bus2RLSpec" function to convert the bus object to RL spec before passing the observation to the agents.
To know more about the "bus2RLSpec" function, refer to the following documentation:
Hope this Helps!
