Fetching 1 or more Months of Reports of multiple Groups of Devices

I'm having a problem when retrieving the summary reports using the API endpoint 'reports/summary'. When I retrieve the report for a duration of 1 to 3 days, it is successful. However, when the time difference increases (let's say 1 week), it fails to fetch the data.

Does it timeout?

Sometime it takes 15 mins to timeout on my Postman and giving back 503 error

And nothing in the payload or the logs?

These are the details:

{
    "servlet": "org.glassfish.jersey.servlet.ServletContainer-53feeac9",
    "message": "Service Unavailable",
    "url": "/api/reports/summary",
    "status": "503"
}

503 Service Unavailable using Postman.

My Server details:
OS: CentOS Stream 9
System: PowerEdge T30
CPU: Intel Xeon E3-1225 v5 @ 3.700GH
Memory: 8GB DDR4

My guess is there's some timeout.

I already increased the timeout on my request but still no luck:

 $.ajax({
                url: '../process/process.php',
                type: 'POST',
                data: {
                    kilometers: true,
                    fromDateKilometers: from_date_converted,
                    toDateKilometers: to_date_converted,
                    timeout: 10000, // Set timeout to 10 seconds
                }

I'm talking about the backend timeout.

How do we increase the backend timeout ?

I don't have an answer. You would have to do some research.