When I try to create a custom RPC on http://localhost:3000/ on Metamask, it keeps on trying to connect to it. It has not moved past "Connecting to Unknown Private Network" on the Metamask extension. What am I doing wrong and how to solve this issue?
As TheCooocy highlighted in his answer, this happens when the RPC port is run on a different port than the web application port.
geth --identity “LocalTestNode” --rpc --rpcport 8080 --rpccorsdomain “*” --datadir ~/mychain/data/ --port 0 --nodiscover --rpcapi db,eth,net,web3,personal --networkid 1999 --maxpeers 0 console
My RPC port here was 8080 and when I did that it worked.