According to the announcement on 17 May 2021 regarding the scheduled suspension of Cardano (ADA) deposit and withdrawal to upgrade the system.
We are glad to inform you that ADA system upgrading is completed and back online.

Schedule
Issue     ADA System Upgrading Completed
Date      27 May 2021
From     08:20 PM (GMT+7)

Due to the recent complaint that Bitkub has suspended the deposit and withdrawal for ADA (Cardano) in order to upgrade the system in 2 phases from 17 May to 27 May 2021, in a total of 10 days.
The upgrade, especially the second phase, as announced by the developer of Cardano network, aimed to improve the efficiency of Smart Contract and Wallet functions. However, the issues that arose from the upgrade have affected some functionalities of the Wallet.
In order to prevent any damages to customers' assets, Bitkub has decided to temporarily suspend deposit and withdrawal for ADA (Cardano), while keeping track of Cardano's developer in order to make sure that the network is back to normal function. Meanwhile, the trading for ADA on Bitkub Exchange was operated normally because they are the circulating supply within the Exchange.
Afterward, our product team confirmed that the first phase upgrade for Cardano is complete, hence the deposit and withdrawal for ADA are also back in service on Bitkub. For the second phase upgrade, we will make another announcement at a later date.

We are truly sorry for the inconvenience this may have caused. We decided so in order to assure that our customers' assets are safe under our protection.

Bitkub is eternally grateful for your support and understanding.