diff --git a/modules/core/src/main/java/org/apache/ignite/internal/managers/discovery/DiscoveryMessageFactory.java b/modules/core/src/main/java/org/apache/ignite/internal/managers/discovery/DiscoveryMessageFactory.java
index 5f399ed0c46fdf..5bc6cbbe945d52 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/managers/discovery/DiscoveryMessageFactory.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/managers/discovery/DiscoveryMessageFactory.java
@@ -34,6 +34,8 @@
 import org.apache.ignite.internal.codegen.TcpDiscoveryPingRequestSerializer;
 import org.apache.ignite.internal.codegen.TcpDiscoveryPingResponseSerializer;
 import org.apache.ignite.internal.codegen.TcpDiscoveryRingLatencyCheckMessageSerializer;
+import org.apache.ignite.internal.codegen.UserAcceptedMessageSerializer;
+import org.apache.ignite.internal.processors.authentication.UserAcceptedMessage;
 import org.apache.ignite.plugin.extensions.communication.MessageFactory;
 import org.apache.ignite.plugin.extensions.communication.MessageFactoryProvider;
 import org.apache.ignite.spi.discovery.tcp.messages.InetAddressMessage;
@@ -62,6 +64,7 @@ public class DiscoveryMessageFactory implements MessageFactoryProvider {
         factory.register((short)-101, InetSocketAddressMessage::new, new InetSocketAddressMessageSerializer());
         factory.register((short)-100, InetAddressMessage::new, new InetAddressMessageSerializer());
 
+        // TcpDiscoveryAbstractMessage
         factory.register((short)0, TcpDiscoveryCheckFailedMessage::new, new TcpDiscoveryCheckFailedMessageSerializer());
         factory.register((short)1, TcpDiscoveryPingRequest::new, new TcpDiscoveryPingRequestSerializer());
         factory.register((short)2, TcpDiscoveryPingResponse::new, new TcpDiscoveryPingResponseSerializer());
@@ -76,5 +79,8 @@ public class DiscoveryMessageFactory implements MessageFactoryProvider {
         factory.register((short)11, TcpDiscoveryAuthFailedMessage::new, new TcpDiscoveryAuthFailedMessageSerializer());
         factory.register((short)12, TcpDiscoveryDuplicateIdMessage::new, new TcpDiscoveryDuplicateIdMessageSerializer());
         factory.register((short)13, TcpDiscoveryClientMetricsUpdateMessage::new, new TcpDiscoveryClientMetricsUpdateMessageSerializer());
+
+        // DiscoveryCustomMessage
+        factory.register((short)500, UserAcceptedMessage::new, new UserAcceptedMessageSerializer());
     }
 }
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/authentication/UserAcceptedMessage.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/authentication/UserAcceptedMessage.java
index ef87a444cb374e..01357dd20d0a71 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/authentication/UserAcceptedMessage.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/authentication/UserAcceptedMessage.java
@@ -17,7 +17,8 @@
 
 package org.apache.ignite.internal.processors.authentication;
 
-import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.internal.Order;
+import org.apache.ignite.internal.managers.communication.ErrorMessage;
 import org.apache.ignite.internal.managers.discovery.DiscoCache;
 import org.apache.ignite.internal.managers.discovery.DiscoveryCustomMessage;
 import org.apache.ignite.internal.managers.discovery.GridDiscoveryManager;
@@ -25,35 +26,48 @@
 import org.apache.ignite.internal.util.tostring.GridToStringInclude;
 import org.apache.ignite.internal.util.typedef.internal.S;
 import org.apache.ignite.lang.IgniteUuid;
+import org.apache.ignite.plugin.extensions.communication.Message;
 import org.jetbrains.annotations.Nullable;
 
 /**
  * Is sent as an acknowledgement for end (with success or error) of user management operation on the cluster
  * (see {@link UserProposedMessage} and {@link UserManagementOperation}).
  */
-public class UserAcceptedMessage implements DiscoveryCustomMessage {
+public class UserAcceptedMessage implements DiscoveryCustomMessage, Message {
     /** */
     private static final long serialVersionUID = 0L;
 
     /** */
-    private final IgniteUuid id = IgniteUuid.randomUuid();
+    @Order(0)
+    private IgniteUuid id;
 
     /** Operation ID. */
+    @Order(value = 1, method = "operationId")
     @GridToStringInclude
-    private final IgniteUuid opId;
+    private IgniteUuid opId;
 
-    /** Error. */
-    private final IgniteCheckedException error;
+    /** Error message. */
+    @Order(value = 2, method = "errorMessage")
+    private ErrorMessage errMsg;
+
+    /** Constructor. */
+    public UserAcceptedMessage() {
+        // No-op.
+    }
 
     /**
-     * @param opId THe ID of operation.
+     * @param opId The ID of operation.
      * @param error Error.
      */
-    UserAcceptedMessage(IgniteUuid opId, IgniteCheckedException error) {
+    UserAcceptedMessage(IgniteUuid opId, Throwable error) {
         assert opId != null || error != null;
 
+        id = IgniteUuid.randomUuid();
+
         this.opId = opId;
-        this.error = error;
+
+        if (error != null)
+            errMsg = new ErrorMessage(error);
     }
 
     /** {@inheritDoc} */
@@ -61,6 +75,13 @@ public class UserAcceptedMessage implements DiscoveryCustomMessage {
         return id;
     }
 
+    /**
+     * @param id Unique custom message ID.
+     */
+    public void id(IgniteUuid id) {
+        this.id = id;
+    }
+
     /** {@inheritDoc} */
     @Nullable @Override public DiscoveryCustomMessage ackMessage() {
         return null;
@@ -80,19 +101,45 @@ public class UserAcceptedMessage implements DiscoveryCustomMessage {
     /**
      * @return User operation ID.
      */
-    IgniteUuid operationId() {
+    public IgniteUuid operationId() {
         return opId;
     }
 
+    /**
+     * @param opId User operation ID.
+     */
+    public void operationId(IgniteUuid opId) {
+        this.opId = opId;
+    }
+
+    /**
+     * @return Error message.
+     */
+    public ErrorMessage errorMessage() {
+        return errMsg;
+    }
+
+    /**
+     * @param errMsg Error message.
+     */
+    public void errorMessage(ErrorMessage errMsg) {
+        this.errMsg = errMsg;
+    }
+
     /**
      * @return Error.
      */
-    IgniteCheckedException error() {
-        return error;
+    Throwable error() {
+        return ErrorMessage.error(errMsg);
     }
 
     /** {@inheritDoc} */
     @Override public String toString() {
         return S.toString(UserAcceptedMessage.class, this);
     }
+
+    /** {@inheritDoc} */
+    @Override public short directType() {
+        return 500;
+    }
 }