Well, you should always check the wallets of any centralized exchange you are gonna use. Whenever there is a problem with any blockchain, their wallets get on suspension automatically. But have to be restored manually, I guess.
So it looks like this suspension took place with HF 20 debacle and haven't been restored since. Did you check Huobi? In case you are patient enough, you can use DEX like Bitshares, or Rudex.
Where can I check the wallets of exchanges? Any list of them?
Whichever wallet you want to check on any Exchange, go to the Deposit / Withdrawal function of that particular coin and you will know if the wallet is up at that time.
I hope, you knew this already.