You are listening too much to the suggestions of the outer consciousness, “not being able”, etc. etc. Since you did begin to open a little for a time, it shows that you are able. You have to get back to that movement; for that you must persuade this outer vital not to go on repeating, “I am not able, my efforts cannot succeed, I am too crooked etc.”—or if it goes on, you must not listen to it. You must affirm and concentrate on the possibility that was shown you and not on the supposed impossibility.
Ref: Letters on Yoga Vol.IV