Celsius paused withdrawals on Sunday to "stabilize liquidity" and "preserve and protect assets" after Lido's Staked Ether (stETH), a cryptocurrency provided on the platform, began to exhibit abnormalities. The Ethereum 2.0 beacon chain (which will eventually combine with the Ethereum mainnet) symbolizes stETH, designed to be pegged to the value of ETH. As a result, stETH is frequently used as collateral on platforms such as Celsius to borrow ETH. However, as other crypto markets collapsed, stETH's peg to the volatile ETH was recently lost. Celsius would sell up its stETH stores to allow clients to withdraw ETH.
If many clients withdrew protesting the recent de-pegging, Celsius would be forced to sell off a significant portion of its $472 million stETH supply. This would drive down the price of stETH even further, leaving the corporation with inadequate liquidity to meet its ETH obligations to consumers. It's unclear how Celsius would address the situation if stETH remains de-pegged from ETH (as of writing, stETH is now trading at .93 ETH).