Tokens in your account need to be signed and authorized by your wallet when you swap them or create/add liquidity for the first time. Here are the steps to authorize/approve a token for adding liquidity:
1.Click “Authorize XXX” (XXX is the token name) to perform authorization
2.Authorizing a token requires confirmation from your wallet. Please click “Accept” in the “Request Signature” pop-up window.
3.The pop-up box shows that your transaction for authorizing a token has been submitted.
4.Authorization is completed when the upper right of the page shows "confirmed" after a few seconds.