How do we solve it? Cannot maximize a(n) convex expression

Hello everyone, I have a problem, if I maximize R_total or minimize AoI_total function alone, the program can run normally, but when I maximize R_total+1/AoI_total function, there will be an error, please tell me how to solve it? Thank you all

You can;t maximize a convex expression using CVX, because that is not a convex optimization problem.