The NetCloud Manager API is intended to serve requests that can be fulfilled in a reasonable, synchronous, web-request time frame. A “reasonable” amount of time in this context is up to ~10 seconds per request. Large data sets that take longer than ten seconds cause the API gateway to time out and return a 408 time-out response.
You can prevent server time-outs by limiting the scope of your requests.
For example, if a request for a 90-day date/time window is timing out, try 90 individual requests, each for a 1-day time window. If a request across 280,000 routers is timing out, try requesting a smaller subset of those routers at a time. If a request potentially scans through millions of alerts records, try restricting the arguments so that the maximum dataset contains substantially less than a million alerts.