I can not get account info in solana
The error is indicating that the CLI RpcClient can not communicate with the Solana validator.
This is usually caused by not having solana-test-validator running in another terminal. Many make the mistake of thinking that the localhost is running the validator all the time... it's not.
In one terminal do: solana-test-validator which will startup up the local validator
Open a second terminal and do solana account - This will return account info for the default keypair