sendPrivateTransaction returns bad response

Here is my error report for eth_sendPrivateTransaction

Error: bad response (status=400, headers={“date”:“Fri, 31 Mar 2023 02:51:42 GMT”,“content-type”:“application/json”,“content-length”:“29”,“connection”:“close”,“x-amzn-requestid”:“49f29b3f-c768-4918-a7df-e6707a5823df”,“x-amz-apigw-id”:“CoCdzEnziYcFYsQ=”,“vary”:“Origin”,“x-amzn-trace-id”:“Root=1-64264abe-00b789723860943132730347;Sampled=0”}, body=“{"error":"incorrect request"}”, requestBody=“{"method":"eth_sendPrivateTransaction","params":[{"tx":"0x02f87880808502540be400854bc0c16716827f319485ca7b1371c77671d2ccb8480a136ffd38b0c28588058d15e176280000841b9265b8c080a08401020ea16fd6f97ce9661d490f44060d0d829c18a8d6d3c1732844e46db19aa01acff88673e91e9a43440e9f227d3e80d71d9e3d96c979c05b55c9a2146558af","maxBlockNumber":8747331,"preferences":{"fast":true}}],"id":42,"jsonrpc":"2.0"}”, requestMethod=“POST”, url=“https://relay-goerli.flashbots.net”, code=SERVER_ERROR, version=web/5.7.1)

And also for sending bundle transactions, the bundlereceipt returns null and no transaction happens on my address.

Not sure if it’s related to gas fee or some tips to the miner.