I have created two nodes and connected the 1st node with the 2nd node in regtest mode . Now when I make the getblocktemplate command using bitcoin-cli . It fails with bitcoin is downloading the block.
 
Bitcoin core vs v0.16

_admin1@root:~/Projects/bitcoin$ ./src/bitcoin-cli -regtest -port=8333 -rpcport=8332 -rpcuser=test -rpcpassword=test getconnectioncount_
**1**
_admin1@root:~/Projects/bitcoin$ ./src/bitcoin-cli -regtest -port=8333 -rpcport=8332 -rpcuser=test -rpcpassword=test getblocktemplate_
**error code: -10
error message:
Bitcoin is downloading blocks.**
return result;
}
static UniValue estimaterawfee(const JSONRPCRequest& request)
{
    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2)
        throw std::runtime_error(
            RPCHelpMan{"estimaterawfee",
                "\nWARNING: This interface is unstable and may disappear or change!\n"
                "\nWARNING: This is an advanced API call that is tightly coupled to the specific\n"
                "         implementation of fee estimation. The parameters it can be called with\n"
                "         and the results it returns will change if the internal implementation changes.\n"
                "\nEstimates the approximate fee per kilobyte needed for a transaction to begin\n"
                "confirmation within conf_target blocks if possible. Uses virtual transaction size as\n"
                "defined in BIP 141 (witness data is discounted).\n",
                {
                    {"conf_target", RPCArg::Type::NUM, RPCArg::Optional::NO, "Confirmation target in blocks (1 - 1008)"},
                    {"threshold", RPCArg::Type::NUM,  "0.95", "The proportion of transactions in a given feerate range that must have been\n"
            "               confirmed within conf_target in order to consider those feerates as high enough and proceed to check\n"
            "               lower buckets."},
                },
                RPCResult{
            "{\n"
            "  \"short\" : {            (json object, optional) estimate for short time horizon\n"
            "      \"feerate\" : x.x,        (numeric, optional) estimate fee rate in " + CURRENCY_UNIT + "/kB\n"
            "      \"decay\" : x.x,          (numeric) exponential decay (per block) for historical moving average of confirmation data\n"
            "      \"scale\" : x,            (numeric) The resolution of confirmation targets at this time horizon\n"
            "      \"pass\" : {              (json object, optional) information about the lowest range of feerates to succeed in meeting the threshold\n"
            "          \"startrange\" : x.x,     (numeric) start of feerate range\n"
            "          \"endrange\" : x.x,       (numeric) end of feerate range\n"
            "          \"withintarget\" : x.x,   (numeric) number of txs over history horizon in the feerate range that were confirmed within target\n"