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.
}
    else if (request.params[0].get_str() == "start") {
        BlockFiltersScanReserver reserver;
        if (!reserver.reserve()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Scan already in progress, use action \"abort\" or \"status\"");
        }
        const std::string filtertype_name{request.params[4].isNull() ? "basic" : request.params[4].get_str()};
        BlockFilterType filtertype;
        if (!BlockFilterTypeByName(filtertype_name, filtertype)) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Unknown filtertype");
        }
        BlockFilterIndex* index = GetBlockFilterIndex(filtertype);
        if (!index) {
            throw JSONRPCError(RPC_MISC_ERROR, "Index is not enabled for filtertype " + filtertype_name);
        }
        NodeContext& node = EnsureAnyNodeContext(request.context);
        ChainstateManager& chainman = EnsureChainman(node);
        
        const CBlockIndex* block = nullptr;
        const CBlockIndex* stop_block = nullptr;
        {
            LOCK(cs_main);
            CChain& active_chain = chainman.ActiveChain();
            block = active_chain.Genesis();
            stop_block = active_chain.Tip();
            if (!request.params[2].isNull()) {
                block = active_chain[request.params[2].getInt<int>()];
                if (!block) {
                    throw JSONRPCError(RPC_MISC_ERROR, "Invalid start_height");
                }