Pre-authorization refers to the method of obtaining customer authorization to collect fees in advance. It is mostly used in hotels. When you check in, you will be asked to swipe your card first. After swiping the card, the corresponding credit limit of the credit card will be frozen. For example, a question similar to yours is A limit of 36 yuan is frozen. The money will not be deducted immediately, but to prevent customers from defaulting on their bills. If the customer does not pay when checking out, the hotel will directly deduct your fee. ps: Are you booking a hotel? If not, take a look at what transactions you have just made. If not, call the bank customer service to apply for a freeze