diff --git a/OpenTok/Session.cs b/OpenTok/Session.cs
index 630519c..8007f87 100644
--- a/OpenTok/Session.cs
+++ b/OpenTok/Session.cs
@@ -159,7 +159,7 @@ private string BuildDataString(Role role, double expireTime, string connectionDa
             dataStringBuilder.Append(string.Format("session_id={0}", this.Id));
             dataStringBuilder.Append(string.Format("&create_time={0}", (long)createTime));
             dataStringBuilder.Append(string.Format("&nonce={0}", nonce));
-            dataStringBuilder.Append(string.Format("&role={0}", role.ToString()));
+            dataStringBuilder.Append(string.Format("&role={0}", role.ToString().ToLowerInvariant()));
 
             if (initialLayoutClassList != null)
             {
diff --git a/OpenTokTest/TokenTests.cs b/OpenTokTest/TokenTests.cs
index 2ab10fc..6a70fa9 100644
--- a/OpenTokTest/TokenTests.cs
+++ b/OpenTokTest/TokenTests.cs
@@ -24,7 +24,7 @@ public void GenerateTokenTest()
             Assert.NotNull(data["sig"]);
             Assert.NotNull(data["create_time"]);
             Assert.NotNull(data["nonce"]);
-            Assert.Equal(data["role"], Role.PUBLISHER.ToString());
+            Assert.Equal(data["role"], "publisher");
         }
 
         [Fact]
@@ -42,7 +42,7 @@ public void GenerateTokenWithRoleTest()
             Assert.NotNull(data["sig"]);
             Assert.NotNull(data["create_time"]);
             Assert.NotNull(data["nonce"]);
-            Assert.Equal(data["role"], Role.SUBSCRIBER.ToString());
+            Assert.Equal(data["role"], "subscriber");
         }
         
         [Fact]
@@ -61,7 +61,7 @@ public void GenerateTokenWithExpireTimeTest()
             Assert.NotNull(data["sig"]);
             Assert.NotNull(data["create_time"]);
             Assert.NotNull(data["nonce"]);
-            Assert.Equal(data["role"], Role.PUBLISHER.ToString());
+            Assert.Equal(data["role"], "publisher");
             Assert.Equal(data["expire_time"], ((long) expireTime).ToString());
         }
 
@@ -80,7 +80,7 @@ public void GenerateTokenWithConnectionDataTest()
             Assert.NotNull(data["sig"]);
             Assert.NotNull(data["create_time"]);
             Assert.NotNull(data["nonce"]);
-            Assert.Equal(data["role"], Role.PUBLISHER.ToString());
+            Assert.Equal(data["role"], "publisher");
             Assert.Equal(data["connection_data"], connectionData);
         }
 
@@ -101,7 +101,7 @@ public void GenerateTokenWithInitialLayoutClass()
             Assert.NotNull(data["sig"]);
             Assert.NotNull(data["create_time"]);
             Assert.NotNull(data["nonce"]);
-            Assert.Equal(data["role"], Role.PUBLISHER.ToString());
+            Assert.Equal(data["role"],"publisher");
             Assert.Equal("focus", data["initial_layout_class_list"]);
         }