Can't connect to Bitcoin RPC on DigitalOcean server
bitcoin.conf should contain the machine's own IP address as an argument to the rpcbind parameter.

For example, if you are running bitcoind on a machine with IP address 1.1.1.1 and you wish to connect to its RPC server from a different machine, your bitcoin.conf file on machine 1.1.1.1 should contain the line rpcbind=1.1.1.1.