Quick question about Predictive Routing 503 errors during JMeter load test

Quick question about predictive routing capacity limits in US1. i am running jmeter 5.6 to simulate high volume inbound calls using the predictive outbound campaign api endpoints. the goal is to test system stability under load. we are trying to push 200 concurrent prediction requests per second against a single campaign. the environment is a standard sandbox org with default settings. after about 30 seconds of execution, the api starts returning 503 Service Unavailable errors. the error message says “service temporarily unavailable due to high load”. this happens even though our account limits show plenty of available seat capacity. i have checked the architect flow and it is very simple, just a single predict node connected to a queue. no complex logic or data actions involved. the jmeter test plan uses the http request sampler with proper authentication tokens. i am using the latest version of the genesys cloud sdk for java. the request headers include the correct content type and accept types. i have also verified that the campaign is active and has enough agents assigned. the error rate increases linearly with the thread count. at 50 threads, everything works fine. at 100 threads, we see occasional 503s. at 200 threads, most requests fail. i am wondering if there is a specific rate limit for the predictive routing api that is not documented. or maybe there is a configuration setting in the admin console that needs to be adjusted to handle higher concurrency. any help would be appreciated. i need to understand the true capacity limits of the predictive routing feature for our performance testing report. please let me know if you have seen similar behavior or if there are best practices for load testing predictive campaigns. thanks in advance.