If you cannot add a new address to the whitelist, please make sure that the address is relevant for this cryptocurrency.
Then please check that the address is not a Segwit one. At the moment Bequant Global does not support Segwit addresses but this will be updated soon.
To add an address to the whitelist you have to confirm this action via email containing a link which is active for 10 minutes.
If you don’t receive this confirmation email, please refer to this article.