Blank mind

Why sometimes our mind is blank? Just because of lack of knowlege? Insureity??
Mind is most powerful and superfull part in our body. Many peoples grow just because of mind. Blank mind means nothing comes in mind while talking to someone, in interview etc.
Our mind never blank,in one day more than 65000 ideas/things comes in mind. Mind never sleeos.
Lack of knowlege matter nothing while u know how to use a situation in favourable manner. Be positive about every situtation come in life. Knowlege of life must have because to know everything happens for a reason.
So, how to deal with a situation can remove the situation of blank mind. Solving tricks,puzzels gives to ideas and situations to tackle.
Thank you.