function within nested loop

I got this code to find all Th3 and Th4 solutions using function command and for loop as it's repeated process. I got many errors saying

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

Error in Aamna_fun1 (line 5)

F(1) = real(b*exp(1i*Th3)-c*exp(1i*Th4)+r*Th4-Z);

Error in fsolve (line 242)

fuser = feval(funfcn{3},x,varargin{:});

Error in test (line 18)

Sol = fsolve(@Aamna_fun1,x0);

Caused by:

Failure in initial objective function evaluation. FSOLVE cannot continue.

could anyone help me to figure out the problem and fix it ,please.

function F = Aamna_fun1(x) %function to be solved
    Th3 = x(1); %first solution 
    Th4 = x(2); %second solution 
    global b c r Z % constant inputs
    F(1) = real(b*exp(1i*Th3)-c*exp(1i*Th4)+r*Th4-Z); %real part of the eqution for the unknowns 
    F(2) = imag(b*exp(1i*Th3)-c*exp(1i*Th4)+r*Th4-Z) %imeginery part of the equation for the unknowns 
    
    
    Th2= 90 : (360+90); %Th2 input range
    for e= 2:length(Th2); %for loop for Th2
        global b c r Z
        a=2;
        b=8;
        c=2;
        r=4;
        d0=6.92;
        ap=6;
        Th1=0;
        Th5=90;
        Z = d0 +r*pi/2+r*1i-a*exp(1i*Th2); %equation with known variables 
        x0 = [0 0]; % guess for Th3 and Th4
        Sol = fsolve(@Aamna_fun1,x0); % solve the above equation
        Th3s = rad2deg(Sol(1)) %first solution for Th3
        Th4s = rad2deg(Sol(2)) %first solution for Th4
        
        for x0 = [Th3s(e-1) Th4s(e-1)] %repeat the above process but with soultions instead of guessing 0 and 0 
            Th3s(:,e+1) = [rad2deg(Sol(1))] %create an array with all Th3 solutions 
            Th4s(:,e+1) = [rad2deg(Sol(2))]  %create an array with all Th4 solutions 
        end
    end
    Th2 = 90:360+90; %th2 range as above
    
    figure(1) %plot Th2 vs Th3
    plot (Th2,Th3(1,:));
    xlabel ('TH2')
    ylabel ('TH3')
    
    figure(2) %plot Th2 vs Th4
    plot (Th2,Th4(1,:));
    xlabel ('TH2') ;
    ylabel ('TH4') ;

[Adam]

For starters I would rework the code to get rid of

global b c r Z

Whether it causes any of the problems you see here frankly I have no idea, but that is part of their problem, it is very hard to understand exactly what is going on with global variables.

Either way, your comments claim they are constants so define them once, outside the loop, in that case, although Z clearly isn't a constant.

[Mil Shastri]

Can you provide a sample input to the function. That will help identifying the issue.