Downlink is not working properly (OTAA very difficult)

Dear Mr. Brocaar,
We have been running a lora server for a while now, with no special problems, but something new is happening lately.

The OTAA Delay is 5s, I didn’t know it, I don’t enter into the deep details of the LoraWAN specification, but the fact is that most of the time (like 75%) our nodes are not able to join OTAA.
This is quite new, I don’t know if smothing has changed lately.

I want the server to answer before those 5 seconds. How can I configure it ? In the node panel, when the device profile is defined as OTAA? it is not possible to change the RX1 delay of the node.
In the server configuration file, the RX1 delay is already set to 1

class a rx1 delay

RX1_DELAY=1

How can I reduce the time the server takes to answer to OTAA ?

Thanks a lot and cheers again for your extraordinary job !
Luc

I have a doubt about that. Isn’t rx1_delay applicable when OTAA is used? Or we can change that in the config file and is applicable? If not, what can we do if there are latencies and we need more time to ack ConfirmedDataUp frames?

I think that’s been explained by the big boss HERE. It’s supposed to be 5 seconds.