the command "bitcoin-cli getblockstats 0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba" does not work.

It displays "error: Error parsing JSON:0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba"

but it should display the block stats like the documentation says.

also bitcoin-cli getblockstats 0 does not work. block number must be at least 1 to work. But blocks start at 0.

tested with 0.20.1 on freebsd, another user on IRC acknowledged the problem.
* known to be part of a sufficiently high-work chain (anti-dos check).
     */
    bool AcceptBlockHeader(
        const CBlockHeader& block,
        BlockValidationState& state,
        CBlockIndex** ppindex,
        bool min_pow_checked) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    friend Chainstate;
    
    std::chrono::time_point<std::chrono::steady_clock> m_last_presync_update GUARDED_BY(::cs_main) {};
public:
    using Options = kernel::ChainstateManagerOpts;
    explicit ChainstateManager(Options options);
    const CChainParams& GetParams() const { return m_options.chainparams; }
    const Consensus::Params& GetConsensus() const { return m_options.chainparams.GetConsensus(); }
    bool ShouldCheckBlockIndex() const { return *Assert(m_options.check_block_index); }
    const arith_uint256& MinimumChainWork() const { return *Assert(m_options.minimum_chain_work); }
    const uint256& AssumedValidBlock() const { return *Assert(m_options.assumed_valid_block); }
    /**
     * Alias for ::cs_main.
     * Should be used in new code to make it easier to make ::cs_main a member
     * of this class.
     * Generally, methods of this class should be annotated to require this
     * mutex. This will make calling code more verbose, but also help to:
     * - Clarify that the method will acquire a mutex that heavily affects
     *   overall performance.
     * - Force call sites to think how long they need to acquire the mutex to
     *   get consistent results.
     */
    RecursiveMutex& GetMutex() const LOCK_RETURNED(::cs_main) { return ::cs_main; }