Error 10003 Invalid arguments in callback function

Hello, 

I am trying to get the values of the GRBVariables inside the callback function of a user-defined class inherited from GRBCallback. However when i run getSolution() or setSolution the error 10003 invalid arguments arise. May you help me find out what am i doing wrong? . I paste the  code down below.

GRBVar* init_arrival(GRBModel& model,vec_pair time_window)
    {
        GRBVar * arrival_time = new GRBVar[customers];

        arrival_time[0] = model.addVar(0.0, GRB_INFINITY, 0.0, GRB_CONTINUOUS, "arrive at depot ");

        for (int i = 1; i < customers; i++)
        {
        
            arrival_time[i] = model.addVar(0.0, time_window[i].second, 0.0, GRB_CONTINUOUS, "arrive at customer " + std::to_string(i));

        }

        return arrival_time;

    }

GRBVar* init_depart(GRBModel& model,vec_pair time_window,float_vec service)
    {

        GRBVar* depart_time = new GRBVar [customers];
    
        depart_time[0] = model.addVar(0.0, 0.0, 0.0, GRB_CONTINUOUS, "depart from depot");

        for (int i = 1; i < customers; i++)
        {

            depart_time[i] = model.addVar(0.0, time_window[i].second + service[i], 0.0, GRB_CONTINUOUS, "depart from customer " + std::to_string(i));

        }

        return depart_time;

    }

void Callbck::callback()
{
    try
    {
        if (where == GRB_CB_MIPNODE)
        {
            double* arrival = new double[customers];

            double* depart = new double[customers];
            

            arrival = getSolution(arrival_time,customers); // Here is where the error occures 

            /*for (int i = 1; i < customers; i++)
            {
                if (arrival[i] < time_window[i].first)
                {
                    setSolution(arrival_time[i], time_window[i].first);
                }
            }
            
            setSolution(depart_time[0], 0.0);

            for (int i = 1; i < customers; i++)
            {
                depart[i] = (arrival[i] > time_window[i].first) ? arrival[i] : time_window[i].first;
                depart[i] += service_time[i];
                setSolution(depart_time[i], depart[i]);
            }

            delete[] arrival;
            delete[] depart;
            */
            
        }
    }
    catch (GRBException e)
    {
        std::cout << "Error number: " << e.getErrorCode() << std::endl;
        std::cout << e.getMessage() << std::endl;

    }
    catch (...)
    {
        std::cout << "Error during callback " << std::endl;
    }
};

Best Regards,