Quantum Espresso

Error in routine stres_hub (1): non-symmetric stress contribution

This error is caused by using vc-relax, tstress and mixing_fixed_ns together.

Solution: Just use scf for calculation, and set tstress=False, also with mixing_fixed_ns = 50 as a starting point. The error will be gone and you will get more accurate initial wavefunction for your further simulations.