Utilize CVXPY to Difference of Concave procedure

I try to implement the Difference of Concave procedure to solve the nonconvex Shannon rate formula, but when using CVXPY, it always result in ill-posed status, what is wrong? Can someone indicate me? I am new to convex optimization. Thanks a lot.

This forum is for CVX, which runs under MATLAB, nor CVXPY


Thank you very much.