How to unset fee rate after setting with RPC `settxfee` After setting the fee rate with settxfee -- how do I re-allow bitcoind to set the fee automatically again? Or does the settxfee command only apply to the next outgoing transaction?
Looking at the source code suggests that settxfee 0 should return you to the automatic fee setting.  However this behavior is undocumented and there is a TODO suggesting that it might go away in the future.  Otherwise, you can restart bitcoind.