This is what Mother said about it
It is not an undesirable thing for the mind to fall silent, to be free from thoughts and still — for it is oftenest when the mind falls silent that there is the full descent of a wide peace from above and in that wide tranquillity the realisation of the silent Self above the mind spread out in its vastnesses everywhere. Only, when there is the peace and the mental silence, the vital mind tries to rush in and occupy the place or else the mechanical mind tries to raise up for the same purpose its round of trivial habitual thoughts. What the sadhaka has to do is to be careful to reject and hush these outsiders, so that during the meditation at least the peace and quietude of the mind and vital may be complete. This can be done best if you keep a strong and silent will. That will is the will of the Purusha behind the mind; when the mind is at peace, when it is silent one can become aware of the Purusha, silent also, separate from the action of the nature.
To be calm, steady, fixed in the spirit, dhı ̄ra, sthira, this quietude of the mind, this separation of the inner Purusha from the outer Prakriti is very helpful, almost indispensable. So long as the being is subject to the whirl of thoughts or the turmoil of the vital movements one cannot be thus calm and fixed in the spirit. To detach oneself, to stand back from them, to feel them separate from oneself is indispensable.
For the discovery of the true individuality and building up of it in the nature, two things are necessary, first, to be conscious of one’s psychic being behind the heart and, next, this separation of the Purusha from the Prakriti. For the true individual is behind veiled by the activities of the outer nature.
Sri Aurobindo, Letters on Yoga II, CWSA volume 29, page 160.
To clarify further – there is a vacant mind on the way to spirituality. There is a vacant mind that is tamas
Thus, you need a discerning intellect to know the difference. If there is ego, vanity, then the mind will think the tamas blank mind is progress
But one thing is certain. God is there. If the earnest desire is there. Genuine desire is there then success is due to come. Don’t waver. Don’t give up
God is kind. Loving. Continue. Without fear. Without depression. With enthusiasm. With determination. Success has to come