The truth is some times banks run out of cash due demand on cash and they only give out the cash that has been deposited by some one else
So it normal for banks to be with out cash and this normal happens during the seasons like X mass, Ramadan etc where people are celebrating and everyone is trying to withdraw money from the bank
This often happens, during major holidays there are large withdrawals due to welcoming the holidays so it is not surprising that most banks run out of money. Even if you want to withdraw a large amount of cash, you need to inform the bank in advance because not all bank branches have large amounts of cash. This is why I never save money in the bank in larger amounts, because the money in the bank is only a number. What actually happens when we save our money in the bank is that the money will be lent to other customers. That's why it happens a lot. Those who save cash find it difficult to actually use the cash. So there is no point in keeping cash other than for emergency purposes, we are better off investing in bitcoin and gold.