Several things could be going on here. Horizontal wells generally last a long time, so unless there was a mechanical problem, this is probably something else. Check your Division Order. It probably had a minimum payment of $100. I usually reset mine to $25 so I get more regular checks once it goes below the $100 minimum.
I wouldn’t be too quick to sell there. You need to think of more than one well. Are you getting paid on one well? Longfellow had permission for another well in 2018. SK Nemaha may still have it planned or not.
Also, if other wells are nearby and getting fracked, your well may be shut in for safety, so a month or two may have low royalties until it starts back up again.
Stone Creek has pending additional horizontal wells in section 23 just west of you, so you might want to see how those pan out before thinking of selling.