Hello Team, PFA pics representing the flow of request with numbering and explanation of the same. https://ibb.co/pQbq2pp https://ibb.co/6RJ0KwB Issue Api gateway is sending PrematureCloseException: Connection prematurely closed BEFORE response in return. The team owning the api gateway server claims that they are getting close event from the spring boot app server (undertow) as shown in point 5. example Received a TLS close_notify, closing the channel now. I need help in resolving this issue whether we have to change any property at undertow side for example noRequestTimeout or keep-alive or we have to change any undertow thread configs example io threads or worker threads. Thanks Vikas Undertow lover