I would like to minimize this function

trace(B*R1). trace_inv(R2B)
–where B is the matrix I need to optimize, B is a Hermitian matrix and R1 ,R2 are both the known matrix. I remember that trace_inv and trace are both convex problem. Howerer, I get the error that
” ??? Error using ==> cvx.times at 173
Disciplined convex programming error:
Cannot perform the operation: {real affine} .* {convex}”

So what is the problem?