Rak7249 and RAK7200 AU915 don't get joined

I have several units of RAK7200 and a Gateway RAK7249 in AU915.
The devices try to join, on the LoRaWAN packet logger I see that the GateWay send the joined confirmation, but the devices still not joined. I see on the RAK SERIAL DEVICE PROTOCOL.
I changed all to AS923 and worked very fine, but in AU915 not.
Please, I need to know why.

Check the channel mask. AU915 uses channel block 2. Sometimes you need to mask ch0-7 off and 8-14 on to make nodes work.

Thank you.
Now is working, my actual problem is understand the Payload that I get in the RAK7249.