DashCoin insight setup in ubuntu system
Try this configuration. It worked for me it might work for you too.

server=1
whitelist=0.0.0.0/0
txindex=1
addressindex=1
timestampindex=1
spentindex=1
zmqpubrawtx=tcp://127.0.0.1:28332
zmqpubrawtxlock=tcp://127.0.0.1:28332
zmqpubhashblock=tcp://127.0.0.1:28332
rpcuser=dash
rpcpassword=local321
rpcport=9998
rpcallowip=0.0.0.0/0
uacomment=bitcore
debug=0
testnet=1