I tried rpcport=9998 and now I get
-342: non-JSON HTTP response with '401 Unauthorized' from server
Cannot connect to desired. Please ensure desired is running and the JSONRPC port is open to Sentinel.
Please help me!
So its replying with Unauthorized, probably because there is a mismatch with the settings when it started and the ones you have now, look at this post and do step 1.
https://bitcointalk.org/index.php?topic=2272607.msg24525799#msg24525799(always do backups!)