Downlink data rate

Hi All

We have limited signal coverage in our CLASS C network and my device is sending on SF12 to the gateway, however gateway it sending downlink on SF9 back to the device which sometimes does not get received. Is there a way in the API downlink callback to enforce a spreading factor back to the end node? not sure why the ADR is choosing SF9. (i have selected SF12 for RX2 in the gateway setup)

TIA!
X

please look at the recommendations, the use of high sff are totally discourage

so using sf12 is not good, move the node or install another gateway to improve the sf