Estimate Fee returning -1 I updated the bitcoin node to version to 140200 on top of which one of my applications was running. There wasn't any issue with the flow of the application estimatefee RPC I get -1 for no matter what I give as the number of blocks. Also the alternate fee api estimatesmartfee returns negative values. 
When I execute the same api on a node with version 140100 it gives me a positive result
How do I resolve this ?
-1 means "not enough information for an accurate estimation".

Try with a higher confirmation target.