Libra on testnet, establish account, give account mint coin shows mint request submitted, of course, this does not mean mint has been successful, but cannot verify,
But the error check account balances, according to the following:

Libra % query balance 0
[ERROR] Failed to get the balance: the Codec (DecodeError {description: "invalid wire type: LengthDelimited (expected Varint)", the stack: [(" AccumulatorProof ", "bitmap"), (" AccountStateProof ", "ledger_info_to_transaction_info_proof"), (" AccountStateWithProof ", "proof"), (" GetAccountStateResponse ", "account_state_with_proof"), (" ResponseItem ", "response_items"), (" UpdateToLatestLedgerResponse ", "response_items")]})

Above, how to deal with,