Session Authentication not working in Play when using Silhouette - playframework-2.6

Question

I am using Silhouette security library. My Play server seem to send empty Session information in response. What am I doing wrong?
Following is the print on Play's console just before sending response.
Session(Map(authenticator -> 1-jtwBvA+LsLKE2rnkT/nMH1aQF9xc1twhECrma9mj3NUhUdVDmh/4wxQ2MxDOjcxkvEMTi1k63Dg5ezl+9FzDE3miaM5DbOrhyqAyGu4+30mHHV3QdPKA3IQQx5UdL1Hu85fZRI4f3Ef+q6xAgboDps0uBob5ojzo5Oqy8FNsoexn7Wr9iRyTr5xrMrLvl9GNQa+rA3q8qvW84sJaSei2iydrP2OjUbnnzo+zgrHLB3Bn7KJxOcFH4h9CikZNk/FHbtDm4uxzcK3paK1CuuIWLE8yvcYdavJ+4ejV5IaJ8QesJQRFgBktD9L/A2bc03eaA8wm)))
But in the the browser window, I notice that the value is empty.
Set-Cookie: PLAY_SESSION=; Max-Age=-86400;
Note that my browser earlier already had a PLAY_SESSION cookie from previous test runs. However, I would expect that the client application (Angular) would override old cookies with new cookies. Am I correct?
Following is the code snippet which creates, initialised and embed session information
val AuthenticatorFuture: Future[SessionAuthenticator] = silhouette.env.authenticatorService.create(loginInfo) //create authenticator
AuthenticatorFuture.flatMap(authenticator => { //got the authenticator
val securityTokenFuture: Future[Session] = silhouette.env.authenticatorService.init(authenticator) //init authenticator
securityTokenFuture.flatMap(securityToken=> {
println("adding security token: ",securityToken)
val result:Future[AuthenticatorResult] = silhouette.env.authenticatorService.embed(securityToken, Ok(Json.toJson(JsonResultSuccess("found user"))))
result
The Environment is defined as
trait SessionEnv extends Env {
type I = User
type A = SessionAuthenticator
}
As is passed to my controller as
silhouette: Silhouette[SessionEnv]
I created is at compile time as follows
val configSession = SessionAuthenticatorSettings()
val sessionAuthenticatorService = new SessionAuthenticatorService(configSession,fingerprintGenerator,authenticatorEncoder,new DefaultSessionCookieBaker(),clock)
val sessionEnv = com.mohiva.play.silhouette.api.Environment[SessionEnv](userIdentityService,sessionAuthenticatorService,Seq(),EventBus())

Answer 1

The issue is probably expected behavior of Play Framework as Silhouette doesn't modify the session cookie. I noticed that the browser already had a previous expired cookie and it sends it in the signin request. When Silhouette authenticator sees the expired cookie, it sends an empty value back. I think this is to make the browser discard the previous cookie.