Issue: OTAA Failed Keys with B-L072Z-LRWAN1

I am trying to use the example in my B-L072Z-LRWAN1 and I am obtaining this error. I have configured a Dragino Lorawan Gateway and I am using the services provided by resiot.io (free version) I have added the the DevUID, AppEUI and app keys in the mbed_app.json file ( "platform.stdio-convert-newlines": true, "platform.stdio-baud-rate": 115200, "platform.default-serial-baud-rate": 115200, "lora.over-the-air-activation": true, "lora.duty-cycle-on": true, "lora.phy": "EU868", "lora.device-eui": "{ 0x00, 0xef, 0x78, 0xfc, 0xc0, 0xb8, 0xe0, 0xab }", "lora.application-eui": "{ 0x70, 0xb3, 0xd5, 0x7e, 0xd0, 0x00, 0xfc, 0xda }", "lora.application-key": "{ 0xf3,0x1c,0x2e,0x8b,0xc6,0x71,0x28,0x1d,0x51,0x16,0xf0,0x8f,0xf0,0xb7,0x92,0x8f}"

).

Any idea of what could be the problem?