How to avoid errors when trying to run a load test in Jmeter with a large number of users (from 100)?

Question

Software testing

It is necessary to test any site with the number of users - 1000.
Based on the results, generate a report.
Initial parameters.
Thread Group / Number of Threads (users): 1000 / Ramp-Up Period: 50 / Loop Count: 1
As a result, the test stopped at 994 users, the remaining 6 will not reach the end, the number of errors is 69%, among them
Response code: 503
Response message: Service Temporarily Unavailable
Response code: Non HTTP response code: java.net.SocketTimeoutException
Response message: Non HTTP response message: Read timed out
Please tell me what is the problem that the test does not reach 1000 users and does not end?
Why is there such a large number of errors, the tested sites are quite popular and, for sure, withstand the load and more?

Answer 1

You can start by monitoring the load station and the servers where the application is deployed and make sure that there is no shortage of resources.
> Response code: Non HTTP response code: java.net.SocketTimeoutException
Load served from windows machine?