diff --git a/dmp-backend/web/src/main/java/eu/eudat/logic/managers/DataManagementPlanManager.java b/dmp-backend/web/src/main/java/eu/eudat/logic/managers/DataManagementPlanManager.java
index ff2f20ab2..7b9555121 100644
--- a/dmp-backend/web/src/main/java/eu/eudat/logic/managers/DataManagementPlanManager.java
+++ b/dmp-backend/web/src/main/java/eu/eudat/logic/managers/DataManagementPlanManager.java
@@ -341,6 +341,11 @@ public class DataManagementPlanManager {
         UserInfo user = apiContext.getOperationsContext().getDatabaseRepository().getUserInfoDao().find(principal.getId());
         createProjectIfItDoesntExist(newDmp, apiContext.getOperationsContext().getDatabaseRepository().getProjectDao(), user);
         newDmp.setCreator(user);
+        List<UserDMP> users = new ArrayList<>();
+        UserDMP userDMP = new UserDMP();
+        userDMP.setUser(user);
+        users.add(userDMP);
+        newDmp.setUsers(new HashSet<>(users));
         newDmp = apiContext.getOperationsContext().getDatabaseRepository().getDmpDao().createOrUpdate(newDmp);
         if (dataManagementPlan.getStatus() == DMP.DMPStatus.FINALISED.getValue()) {
             apiContext.getOperationsContext().getDatabaseRepository().getDatasetDao()
diff --git a/dmp-backend/web/src/main/java/eu/eudat/logic/services/utilities/InvitationServiceImpl.java b/dmp-backend/web/src/main/java/eu/eudat/logic/services/utilities/InvitationServiceImpl.java
index 72bf72fea..6668fb3cd 100644
--- a/dmp-backend/web/src/main/java/eu/eudat/logic/services/utilities/InvitationServiceImpl.java
+++ b/dmp-backend/web/src/main/java/eu/eudat/logic/services/utilities/InvitationServiceImpl.java
@@ -45,7 +45,7 @@ public class InvitationServiceImpl implements InvitationService {
 
     @Override
     public void assignToDmp(DMPDao dmpDao, eu.eudat.data.entities.UserDMP user, DMP dmp) {
-        if (!dmp.getUsers().stream().map(x -> x.getId()).collect(Collectors.toList()).contains(user.getId())) {
+        if (!dmp.getUsers().stream().map(x -> x.getUser().getId()).collect(Collectors.toList()).contains(user.getId())) {
             dmp.getUsers().add(user);
             dmpDao.createOrUpdate(dmp);
         }
diff --git a/dmp-backend/web/src/main/java/eu/eudat/models/data/dmp/DataManagementPlan.java b/dmp-backend/web/src/main/java/eu/eudat/models/data/dmp/DataManagementPlan.java
index fce6b2968..55c571266 100644
--- a/dmp-backend/web/src/main/java/eu/eudat/models/data/dmp/DataManagementPlan.java
+++ b/dmp-backend/web/src/main/java/eu/eudat/models/data/dmp/DataManagementPlan.java
@@ -274,14 +274,16 @@ public class DataManagementPlan implements DataModel<DMP, DataManagementPlan> {
         if (this.dynamicFields != null)
             dataManagementPlanEntity.setDmpProperties(JSONObject.toJSONString(this.dynamicFields.stream().filter(item -> item.getValue() != null).collect(Collectors.toMap(DynamicFieldWithValue::getId, DynamicFieldWithValue::getValue))));
 
-        List<UserDMP> userDMPList  = new LinkedList<>();
-        for(UserListingModel userListingModel: this.associatedUsers) {
-            UserDMP userDMP = new UserDMP();
-            userDMP.setUser(userListingModel.toDataModel());
-            userDMPList.add(userDMP);
+        if (this.associatedUsers != null && !this.associatedUsers.isEmpty()) {
+            List<UserDMP> userDMPList  = new LinkedList<>();
+            for(UserListingModel userListingModel: this.associatedUsers) {
+                UserDMP userDMP = new UserDMP();
+                userDMP.setUser(userListingModel.toDataModel());
+                userDMPList.add(userDMP);
+            }
+            dataManagementPlanEntity.setUsers((Set<UserDMP>) userDMPList);
         }
 
-        dataManagementPlanEntity.setUsers((Set<UserDMP>) userDMPList);
         return dataManagementPlanEntity;
     }