How to pass inequality constraints to surrogateopt?

Hello,

I have a function that returns the objective and constraint functions to be passed to surrogateopt. However, I receve the following error about the constraint

Error using parallel.FevalFuture/fetchNext

The function evaluation completed with an error.

Error in globaloptim.bmo.ModelManager/getNext (line 155)

[~, self.pendingTrials(fetchID).output] = fetchNext(self.pendingTrials(fetchID).task);

Error in globaloptim.bmo.BlackboxModelOptimizer/optimize (line 170)

trialResponse = self.modelMgr.getNext();

Error in surrogateopt (line 338)

controller = controller.optimize();

Error in thetasol (line 54)

xfinal = surrogateopt(objconstr,lb,ub,intcon, options);

Caused by:

Error using globaloptim.bmo.ModelManager>conditionalModelEvaluator (line 433)

Input arguments to function include colon operator. To input the colon character, use ':' instead.

The function that returns the constraint is as follows

[obj, con]=func1(a,b,c);

objconstr=@(x) struct('Fval',obj,'Ineq',con);

% lb ub, intcon and options have also been appropriately specified and supplied to the optimiser.
xfinal = surrogateopt(objconstr,lb,ub,intcon, options); 

function [obj, con]=func1(a,b,c)
P=[];
obj=@func2;
con=@func3;

    function obj=func2(x)
        %many matrix operations that calculate P using a,b,c and a number
        %of optimsiation variables "x"
        P=somedummyoperation; %P is a nXM matrix
        
        obj=sum(sum(P));
    end

    function con=func3
        load('ref_vector_file','ref_vec');
        buff_var=cross(P(1:2:3,:),ref_vec);
        con=norm(buff_vec);
    end
end

This code however runs when i remove the constraint and optimise (the solution is unacceptable since the problem is poorly defined in this case)

How would I choose to move ahead to to address the error?