That’is why I wrote

`The scaling of your problem may present difficulties. I’ll let you look into that.`

You need to improve the scaling of your problem. The solver apparently is not able to deal well with such small values of `b`

.

Also, I rrecommend you install CVXQUAD per CVXQUAD: How to use CVXQUAD's Pade Approximant instead of CVX's unreliable Successive Approximation for GP mode, log, exp, entr, rel_entr, kl_div, log_det, det_rootn, exponential cone. CVXQUAD's Quantum (Matrix) Entropy & Matrix Log related functions . However, given that CVX’s Successive Approximation method appears to have succeeded, i doubt CVXQUAD will make your results come out better in this case, but I don’t know for sure.

Let’s see whether someone clever comes along who can come up with a nice change of variables or something to improve the formulation of the problem.so that the solver is presented a numeriically nicer problem.