Error using odearguments due to vector incoherent

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I dont understand what i did wrong with my code, i asked AI and it didnt give me any enlighmentment. anybody please help me please :')

clc; clear;
x0=[1;1;1;1;1]
x0 = 5×1
     1
     1
     1
     1
     1
tspan=[0 21]
tspan = 1×2
     0    21
[x,l] = ode45(@f ,tspan,x0);
Error using odearguments
F returns a vector of length 1, but the length of initial conditions vector is 5. The vector returned by F and the initial conditions vector must have the same number of elements.

Error in ode45 (line 107)
    odearguments(odeIsFuncHandle,odeTreatAsMFile, solver_name, ode, tspan, y0, options, varargin);
plot(l,x)

function dxdl=f(l,x)
    d=2;
    Ft=0.85;
    T0=892;
    Cp_Cl=8.6;
    Cp_C3=25.3;
    Cp_AlCl=28.0;
    Cp_2ClC3=30.7;
    Cp_HCl=7.2;
    U=5;
    H1=-48000;
    H2=-79200;
    T_LMTD=-20;
    x1=x(1);
    x2=x(2);
    dT=x(3);
    r1=x(4);
    r2=x(5);
    dx1dl = r1*pi*d^2/(4*Ft);
    dx2dl = r2*pi*d^2/(4*Ft);
    dr1dl = 824000*exp(-13700/(T0+dT))*(0.8-x1-x2)*(0.2-x1-x2)/((1-x2)^2);
    dr2dl = 46.8*exp(-3460/(T0+dT))*(0.8-x1-x2)*(0.2-x1-x2)/((1-x2)^2);
    dCpdT = Ft*((1-5*x1-5*x2)*Cp_Cl+(4-5*x1-5*x2)*Cp_C3+(5*x1)*Cp_AlCl+(5*x2)*Cp_2ClC3+(5*x1)*Cp_HCl);
    dTdl = ((pi*d*U*T_LMTD)-(r1*H1+r2*H2)*pi*d^2/4)/dCpdT;
    dxdl=@(l,x) [dx1dl;dx2dl;dr1dl;dr2dl;dTdl];
end