diff --git a/application/src/main/java/org/thingsboard/server/controller/AlarmController.java b/application/src/main/java/org/thingsboard/server/controller/AlarmController.java
index 005d474c96..dfac4c5c39 100644
--- a/application/src/main/java/org/thingsboard/server/controller/AlarmController.java
+++ b/application/src/main/java/org/thingsboard/server/controller/AlarmController.java
@@ -217,7 +217,7 @@ public class AlarmController extends BaseController {
     @PreAuthorize("hasAnyAuthority('TENANT_ADMIN', 'CUSTOMER_USER')")
     @RequestMapping(value = "/alarm/{alarmId}/assign", method = RequestMethod.DELETE)
     @ResponseStatus(value = HttpStatus.OK)
-    public Alarm assignAlarm(@ApiParam(value = ALARM_ID_PARAM_DESCRIPTION)
+    public Alarm unassignAlarm(@ApiParam(value = ALARM_ID_PARAM_DESCRIPTION)
                             @PathVariable(ALARM_ID) String strAlarmId
     ) throws Exception {
         checkParameter(ALARM_ID, strAlarmId);
diff --git a/common/data/src/main/java/org/thingsboard/server/common/data/alarm/AlarmAssignee.java b/common/data/src/main/java/org/thingsboard/server/common/data/alarm/AlarmAssignee.java
index 1b61f8c94e..abe8626ad7 100644
--- a/common/data/src/main/java/org/thingsboard/server/common/data/alarm/AlarmAssignee.java
+++ b/common/data/src/main/java/org/thingsboard/server/common/data/alarm/AlarmAssignee.java
@@ -15,7 +15,6 @@
  */
 package org.thingsboard.server.common.data.alarm;
 
-import lombok.Builder;
 import lombok.Data;
 import org.thingsboard.server.common.data.id.UserId;
 
diff --git a/dao/src/main/java/org/thingsboard/server/dao/model/sql/AlarmInfoEntity.java b/dao/src/main/java/org/thingsboard/server/dao/model/sql/AlarmInfoEntity.java
index 43483a0165..aa58e9e469 100644
--- a/dao/src/main/java/org/thingsboard/server/dao/model/sql/AlarmInfoEntity.java
+++ b/dao/src/main/java/org/thingsboard/server/dao/model/sql/AlarmInfoEntity.java
@@ -28,8 +28,6 @@ import javax.persistence.Table;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_ASSIGNEE_EMAIL_PROPERTY;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_ASSIGNEE_FIRST_NAME_PROPERTY;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_ASSIGNEE_LAST_NAME_PROPERTY;
-import static org.thingsboard.server.dao.model.ModelConstants.ALARM_COLUMN_FAMILY_NAME;
-import static org.thingsboard.server.dao.model.ModelConstants.ALARM_CUSTOMER_ID_PROPERTY;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_ORIGINATOR_LABEL_PROPERTY;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_ORIGINATOR_NAME_PROPERTY;
 import static org.thingsboard.server.dao.model.ModelConstants.ALARM_VIEW_NAME;
@@ -70,7 +68,9 @@ public class AlarmInfoEntity extends AbstractAlarmEntity<AlarmInfo> {
         AlarmInfo alarmInfo = new AlarmInfo(super.toAlarm());
         alarmInfo.setOriginatorName(originatorName);
         alarmInfo.setOriginatorLabel(originatorLabel);
-        alarmInfo.setAssignee(new AlarmAssignee(new UserId(getAssigneeId()), assigneeFirstName, assigneeLastName, assigneeEmail));
+        if (getAssigneeId() != null) {
+            alarmInfo.setAssignee(new AlarmAssignee(new UserId(getAssigneeId()), assigneeFirstName, assigneeLastName, assigneeEmail));
+        }
         return alarmInfo;
     }
 }