Let us first understand what is liquidity. In the traditional sense of a bank, a liquidity crisis occurs when most of its funds are locked up in long term assets and a lot of depositors ask for their money. Asset classes like real estate and private equity may also be considered illiquid, due to time and effort taken to find buyers.

As far as crypto exchanges are concerned , they are just supposed to hold your coins. In case there is a shortage of buyers at an exchange, you always have the option of withdrawing your coins and selling them at another exchange. So if an exchange has problems, it is not going to be about liquidity.