“queue limit” error

Question

I try to deploy a smart contract and every time i receive "queue limit" error.

Here is what i do:

Web3 = require("web3")
web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
const bytecode = '0x606 ....
const abi = [ ....
web3.eth.personal.unlockAccount('0xa95523067A3bfF1B8aeB41F85D58C7fe2b88fde3', 'logic')
var thisContract = new web3.eth.Contract(abi, {
    from: '0xa95523067A3bfF1B8aeB41F85D58C7fe2b88fde3',
    gasPrice: '20000000000'
});
thisContract.deploy({ data: bytecode }).estimateGas(function(err, gas) { console.log(gas); });
2021348
thisContract.deploy({ data: bytecode }).send({
        from: '0xa95523067A3bfF1B8aeB41F85D58C7fe2b88fde3',
        gas: 2021348,
        gasPrice: '3000000000'
    },
    function(error, transactionHash) {
        console.log(error);
        console.log(transactionHash);
        console.log('function exec');
    }).then(function(newContractInstance) {
    console.log('Contract Instance:' + newContractInstance.options.address);
});

and every time i receive following error, even when i unlock account several times.

> Error: Returned error: Request has been rejected because of queue limit.
    at Object.ErrorResponse (/home/ubuntu/parityewf/node_modules/web3-core-helpers/src/errors.js:29:16)
    at /home/ubuntu/parityewf/node_modules/web3-core-requestmanager/src/index.js:140:36
    at XMLHttpRequest.request.onreadystatechange (/home/ubuntu/parityewf/node_modules/web3-providers-http/src/index.js:77:13)
    at XMLHttpRequestEventTarget.dispatchEvent (/home/ubuntu/parityewf/node_modules/xhr2/lib/xhr2.js:64:18)
    at XMLHttpRequest._setReadyState (/home/ubuntu/parityewf/node_modules/xhr2/lib/xhr2.js:354:12)
    at XMLHttpRequest._onHttpResponseEnd (/home/ubuntu/parityewf/node_modules/xhr2/lib/xhr2.js:509:12)
    at IncomingMessage.<anonymous> (/home/ubuntu/parityewf/node_modules/xhr2/lib/xhr2.js:469:24)
    at emitNone (events.js:91:20)
    at IncomingMessage.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:974:12)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickDomainCallback (internal/process/next_tick.js:128:9)
undefined
function exec
(node:14469) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Returned error: Request has been rejected because of queue limit.

This may be helpful : https://tobalaba.etherscan.com/address/0xa95523067A3bfF1B8aeB41F85D58C7fe2b88fde3