The method eth_sendTransaction does not exist/is not available

Questions
1

I send USDT to other wallet, returned “The method eth_sendTransaction does not exist/is not available”.
Is the method not supported?

2

We do not support the eth_sendTransaction method. That method would require that we were holding the private key to sign the transaction before broadcasting it to the Ethereum network. Infura doesn’t maintain any private keys on your behalf. In order to send a transaction, you need to sign the transaction on your end with your private key, then send to Infura the signed transaction using the eth_sendRawTransaction method.

I hope this helps to clarify.