title: What is the meaning of decode: could not decode JWT in playframework 2.6.x?
body: <p>I am new to PlayFramework, and I am trying to implement a very basic login feature in Java: </p>
  
  <pre><code>session("connected",email);
  </code></pre>
  
  <p>Retrieval:</p>
  
  <pre><code>String user = session("connected");
  </code></pre>
  
  <p>However, whereas putting itens into session actually works (I print into console). When I try to retrieve it, it returns null, and I have the following exception:</p>
  
  <pre><code>[warn] p.a.m.DefaultJWTCookieDataCodec - decode: could not decode JWT: JWT signature does not match locally computed signature. JWT validity cannot be asserted and should not be trusted.
  io.jsonwebtoken.SignatureException: JWT signature does not match locally computed signature. JWT validity cannot be asserted and should not be trusted.
          at io.jsonwebtoken.impl.DefaultJwtParser.parse(DefaultJwtParser.java:354)
          at io.jsonwebtoken.impl.DefaultJwtParser.parse(DefaultJwtParser.java:481)
          at io.jsonwebtoken.impl.DefaultJwtParser.parseClaimsJws(DefaultJwtParser.java:541)
          at play.api.mvc.JWTCookieDataCodec$JWTFormatter.parse(Cookie.scala:652)
          at play.api.mvc.JWTCookieDataCodec.decode(Cookie.scala:577)
          at play.api.mvc.JWTCookieDataCodec.decode$(Cookie.scala:569)
          at play.api.mvc.DefaultJWTCookieDataCodec.decode(Cookie.scala:742)
          at play.api.mvc.FallbackCookieDataCodec.decode(Cookie.scala:728)
          at play.api.mvc.FallbackCookieDataCodec.decode$(Cookie.scala:719)
          at play.api.mvc.DefaultSessionCookieBaker.decode(Session.scala:95)
  </code></pre>
  
  <p>What is the cause of this?</p>
  
  <p>My application.conf</p>
  
  <pre><code>application.secret="I70pMkPNKJ5o6eq&lt;I7:X@DF?evtvUQd7HSCn&gt;I7mPHTt6fL8]HsFdNq5;DfH0JAo"
  
  db.default.driver=org.h2.Driver
  db.default.url="jdbc:h2:mem:play;MODE=PostgreSQL"
  
  ebean.default=["models.*"] 
  
  play.filters.enabled += "play.filters.headers.SecurityHeadersFilter"
  play.filters.headers.contentSecurityPolicy = null
  
  application.mode=dev
  </code></pre>
  
  <p>My plugins.sbt</p>
  
  <pre><code>addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.6.0")
  addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "5.1.0")
  addSbtPlugin("com.typesafe.sbt" % "sbt-play-ebean" % "4.0.2") 
  </code></pre>