Matrics with the same dimension cannot be plused in cvx

both diag2 and temp2 are cvx complex affine expressions(6x6 matrics)

the codes are shown below

for b = 1:Num_Block
cvx_begin sdp quiet
variable w(Num_tx,1) complex
variable tu nonnegative
variable te nonnegative
variable lamda nonnegative
variable miu nonnegative

        diag_theta_former_b = diag(exp(1i.*theta_former(:,b)));
        % M1
        expression temp1(Num_ele+3,Num_ele+3) 
        diag1 = blkdiag(te-lamda,1-lamda,lamda*eye(Num_ele+1));
        temp1(:,1) = [0;((Channel_gr_bar(:,b)'*diag_theta_former_b*Channel_G(:,:,b)+Channel_gd(:,b)')*w)';zeros(Num_ele+1,1)];
        temp1(:,2) = [(Channel_gr_bar(:,b)'*diag_theta_former_b*Channel_G(:,:,b)+Channel_gd(:,b)')*w;0;ke(1,b)*(diag_theta_former_b*Channel_G(:,:,b)*w);0];
        m1 = diag1 + temp1 + temp1';
        % M2
        F1 = diag_theta_former_b*Channel_G(:,:,b)*w*w_former(:,b)'*Channel_G(:,:,b)'*diag_theta_former_b' ...
            + diag_theta_former_b*Channel_G(:,:,b)*w_former(:,b)*w'*Channel_G(:,:,b)'*diag_theta_former_b' ...
            - diag_theta_former_b*Channel_G(:,:,b)*w_former(:,b)*w_former(:,b)'*Channel_G(:,:,b)'*diag_theta_former_b';
        f2 = diag_theta_former_b*Channel_G(:,:,b)*w*w_former(:,b)'*Channel_hd(:,b) ...
            + diag_theta_former_b*Channel_G(:,:,b)*w_former(:,b)*w'*Channel_hd(:,b) ...
            - diag_theta_former_b*Channel_G(:,:,b)*w_former(:,b)*w_former(:,b)'*Channel_hd(:,b);
        f3 = Channel_hd(:,b)'*(w*w_former(:,b)'+w_former(:,b)*w'-w_former(:,b)*w_former(:,b)')*Channel_hd(:,b);
        f4 = Channel_hr_bar(:,b)'*F1*Channel_hr_bar(:,b)+Channel_hr_bar(:,b)'*f2+f2'*Channel_hr_bar(:,b)+f3;
        expression temp2(Num_ele+1,Num_ele+1)
        diag2 = blkdiag(eye(Num_ele)+F1,f4-tu-miu*ku(1,b)^2);
        temp2(:,1:Num_ele) = [zeros(Num_ele,Num_ele);Channel_hr_bar(:,b)'*F1+f2'];
        m2 = diag2 + temp2 + temp2';    %%%%% where the problem arises
        
        maximize(tu/Noise_Var_u-te/Noise_Var_e)
        
        subject to
        norm( w ) <= sqrt(P);
        m1 >= 0;
        m2 >= 0;
    
    cvx_end
    
    w_opt(:,b) = w;
end

What is the exact error message you are encountering, and on what line of code?