What are the reasons for this situation? Can you help me

I have many posts. Crude, unsafeguarded (no line search or trust region) SCA is very unreliable, and often fails when applied to new problems. It may not converge to anything, and if it does, it may not be a global or even local optimum. You may be better off using an existing non-convex solver (for instance, under YALMIP) than writing your own SCA.