Receiving Data with events Api

Hello everybody.
I am building an API to send data, and then check if the device got the data.
The device is a siren. So I need to know if the siren is making a sound.
The first part of the API is working properly, since I am able to send data, and get the frame counter:
{ "fCnt": 421}
I enabled ack on the device. So every time I send data to the siren, in the “lorawan frames” o “Device Data” I see the confirmeddatadown packet or the txack and ack packet.

If I unplug the siren, I still get the framecounter response. Thats the reason I need to confirm the siren is functional an ready

According with this information:
There is an end point to capture the lorawan frames or events.
But none of them are working. I dont get any data.
Using postman, to test the endpoint /api/devices/{dev_eui}/events], the only thing I get is a header, the body is empty.

To build the API I am using laravel.

On the other hand, in the integration I am using influxdb. I get on the database all the uplinks, but no the downlinks, niether the ack. Should I get the downlinks and ack too?.
I f I can get the ack or the downlinks in the database, thats will be useful to confirm the siren is working properly.

I appreciate if anybody can give me an advice how to use the endpoint to get the lorawan frames, or store the ack and downlinks in the database.

Best regards