Same issue here. I notice the following from the kucoin web site documentation.
Perhaps it is relevant :
Upcoming changes To reinforce the security of the API, KuCoin upgraded the API key to version 2.0, the validation logic has also been changed. It is recommended to create and update your API key to version 2.0. The API key of version 1.0 will be still valid until May 1, 2021. Check new signing method
Yes, as mentioned by another user, Koinly doesn’t support IP whitelisting yet. So please set your accounts to “read-only” when you make the API credential on your exchanges, and no whitelisting. That’s all we need.
I just started my wallets and the only one i am having trouble syncing is the API on Kucoin. i selected no on the limiting of the IP address and still doesn’t sync??