How to fix Odearguments errors ode45 function

A = [0 1;-20 -10];

B = [0;10];

p=[-40;-50]

C2 = poly(A);

w=[C1(2) 1;1 0];

T=C*w;

C3 = poly(p);

K=[C3(3)-C2(3) C3(2)-C2(2)]*inv(T);

X0= [0.3;0];

Xref = [3;0];

%solver

Tspan=[0 5];

[t,x] = ode45(@spring, Tspan, X0);

function Y = spring(t,x)

global K Xref A B

X = [x(1);x(2)];

u = K*(Xref-X);

Y= A*X+B*u;

I am getting the following error, can some please help

Error using -

Arrays have incompatible sizes for this operation.

Error in spring (line 4)

u = K*(Xref-X);

Error in odearguments (line 90)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in First_second (line 44)

[t,x] = ode45(@spring, T, X0);