I am new to this mining, I started yesterday with downloading the chains for geth and today it finished and so I got the newest version of ethminer. But when I start it this comes:

JSON-RPC problem. Probably couldn't connect. Retrying in 1... m 17:30:29|main Getting work package... X 17:30:30|main Failed to submit hashrate. X 17:30:30|main Dynamic exception type: class jsonrpc::JsonRpcException std::exception::what: Exception -32003 : Client connector error: libcurl error: 7 -> Could not connect to

I have searched in several Forums about this, but I don't know what to do? Please help thanks! Btw. I am using the latest version of windows 10 and use a gtx 1060 3gb. Andy

  • Hi there. It looks like your mining software isn't able to connect to Geth on port 8545. What command and flags did you use to start Geth? Jun 27, 2017 at 15:54
  • I just used geth -rpc in the command prompt and that just added chains and did his thing.
    – user12013
    Jun 27, 2017 at 15:57
  • Try restarting Geth using --rpc --rpcport 8545. Jun 27, 2017 at 16:02
  • Great - glad it worked! :-) Jun 27, 2017 at 16:09

1 Answer 1


As per the comment discussion, this error:

libcurl error: 7 -> Could not connect to

...is the important part.

To ensure Geth exposes this port (8545) as an RPC interface, it should be started with the --rpc --rpcport 8545 options.

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