It seems that for Play 2.6 akka http instead of netty is used for the backend. This means that a default timeout configuration is set for the akka http server.
The idle timeout can be increased by adding the following to the applications.conf file.
play.server.http.idleTimeout = 180s
However according to the play documentation:
Note: In dev mode, when you use the run command, your application.conf settings will not be picked up by the server. This is because in dev mode the server starts before the application classpath is available.
Thus for testing with longer idleTimeout one could run the play instance using:
sbt run -Dplay.server.http.idleTimeout=180s
For further documentation see:
https://www.playframework.com/documentation/2.6.x/SettingsAkkaHttp
http://doc.akka.io/docs/akka-http/current/java/http/server-side/websocket-support.html
akka.http.server.idle-timeout
have no effect in the play framework? – Delay