WASSessionCor W SessionAffinityManager setCookie SESN0066E: The response is already validated for the client. The session cookie can not be set

Question

I'm using application web using spring and WebSphere server 8.5

I have this error in my console after trying to authenticate:

WASSessionCor W SessionAffinityManager setCookie SESN0066E: The response is already validated for the client. The session cookie can not be set.

I have a problem with my configuration with WAS 8 but I don't know which one.

If someone had already the same problem to tell me which configuration should I edit.

Answer 1

This doesn't look like a configuration issue, it's an application issue. Fortunately, this is a programming Q&A site.

This error means you established a new HTTP Session after the response headers (and usually some of the body) have been flushed to the client. Establishing a new session requires sending a cookie, and HTTP headers come before the body.

You likely have an FFDC that shows you the stacktrace of where this session init happened. You need to restructure your code so it happens before any of the body is written/flushed.