AAVE deposit, insufficient balance on polygon chain

I would like to try AAVE with polygon chain. Therefore I have got USDT, MATIC and ETH bridged to my Metamask wallet on polygon chain. However when I try to deposit USDT to AAVE, it keeps saying insufficient balance. I am not sure what is missing.
Anyone know what I might have been missed? Would be great if there is any suggestion. I am new to defi. Thanks!