My problem can be solved by SDPT3 but not by SeDuMi. WHY?

[Mark_L_Stone]

I recommend you read 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 .

Bottom line: Use CVX 2.2 with Mosek 9.x as solver if avallable to you… Otherwise, install CVXQUAD and follow the directions in the link.