diff --git a/DigitalData.UserManager.Application/DigitalData.UserManager.Application.csproj b/DigitalData.UserManager.Application/DigitalData.UserManager.Application.csproj
index 450a81c..c5ebbac 100644
--- a/DigitalData.UserManager.Application/DigitalData.UserManager.Application.csproj
+++ b/DigitalData.UserManager.Application/DigitalData.UserManager.Application.csproj
@@ -29,6 +29,7 @@
     <PackageReference Include="AutoMapper" Version="13.0.1" />
     <PackageReference Include="DigitalData.Core.Abstractions" Version="3.1.0" />
     <PackageReference Include="DigitalData.Core.Application" Version="3.0.1" />
+    <PackageReference Include="DigitalData.Core.DTO" Version="2.0.1" />
     <PackageReference Include="DigitalData.EmailProfilerDispatcher.Abstraction" Version="2.0.0" />
     <PackageReference Include="Microsoft.Extensions.Localization.Abstractions" Version="7.0.16" />
     <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="7.0.0" />
diff --git a/DigitalData.UserManager.Application/Services/GroupService.cs b/DigitalData.UserManager.Application/Services/GroupService.cs
index 752cd10..551a160 100644
--- a/DigitalData.UserManager.Application/Services/GroupService.cs
+++ b/DigitalData.UserManager.Application/Services/GroupService.cs
@@ -10,8 +10,8 @@ namespace DigitalData.UserManager.Application.Services
 {
     public class GroupService : BaseService<IGroupRepository, GroupCreateDto, GroupReadDto, Group>, IGroupService
     {
-        private readonly IStringLocalizer<Resource> _localizer;
-        public GroupService(IGroupRepository repository, IStringLocalizer<Resource> localizer, IMapper mapper) : base(repository, mapper)
+        private readonly IStringLocalizer<Resource>? _localizer;
+        public GroupService(IGroupRepository repository, IStringLocalizer<Resource>? localizer, IMapper mapper) : base(repository, mapper)
         {
             _localizer = localizer;
         }
@@ -25,7 +25,7 @@ namespace DigitalData.UserManager.Application.Services
             group.AddedWho = user?.AddedWho ?? "UNAUTHORIZED";
 
             if (await HasEntity(group.Id))
-                return Result.Fail<int>().Message(_localizer[Key.GroupAlreadyExists.ToString()]);
+                return Result.Fail<int>().Message(_localizer?[Key.GroupAlreadyExists].Value);
 
             var createdGroup = await _repository.CreateAsync(group);
             if (createdGroup is null)
diff --git a/DigitalData.UserManager.Application/Services/UserRepService.cs b/DigitalData.UserManager.Application/Services/UserRepService.cs
index 832a9f4..91204b9 100644
--- a/DigitalData.UserManager.Application/Services/UserRepService.cs
+++ b/DigitalData.UserManager.Application/Services/UserRepService.cs
@@ -11,8 +11,8 @@ namespace DigitalData.UserManager.Application.Services
 {
     public class UserRepService : BaseService<IUserRepRepository, UserRepCreateDto, UserRepReadDto, UserRep>, IUserRepService
     {
-        private readonly IStringLocalizer<Resource> _localizer;
-        public UserRepService(IUserRepRepository repository, IStringLocalizer<Resource> localizer, IMapper mapper) : base(repository, mapper)
+        private readonly IStringLocalizer<Resource>? _localizer;
+        public UserRepService(IUserRepRepository repository, IStringLocalizer<Resource>? localizer, IMapper mapper) : base(repository, mapper)
         {
             _localizer = localizer;
         }
@@ -27,10 +27,10 @@ namespace DigitalData.UserManager.Application.Services
         public override async Task<DataResult<int>> CreateAsync(UserRepCreateDto createDto)
             // XOR control
             => (createDto.ValidFrom is null && createDto.ValidTo is not null) || (createDto.ValidFrom is not null && createDto.ValidTo is null)
-                ? Result.Fail<int>().Notice(LogLevel.None, Flag.DataIntegrityIssue, _localizer[Key.DateRangeNotXNOR])
+                ? Result.Fail<int>().Notice(LogLevel.None, Flag.DataIntegrityIssue, _localizer?[Key.DateRangeNotXNOR].Value)
             //date range control
                 : (createDto.ValidFrom > createDto.ValidTo)
-                ? Result.Fail<int>().Notice(LogLevel.None, Flag.DataIntegrityIssue, _localizer[Key.InvalidDateRange])
+                ? Result.Fail<int>().Notice(LogLevel.None, Flag.DataIntegrityIssue, _localizer?[Key.InvalidDateRange].Value)
                 : await base.CreateAsync(createDto);        
     }
 }
\ No newline at end of file
diff --git a/DigitalData.UserManager.Application/Services/UserService.cs b/DigitalData.UserManager.Application/Services/UserService.cs
index a0f062f..fed5110 100644
--- a/DigitalData.UserManager.Application/Services/UserService.cs
+++ b/DigitalData.UserManager.Application/Services/UserService.cs
@@ -10,8 +10,8 @@ namespace DigitalData.UserManager.Application.Services
 {
     public class UserService : BaseService<IUserRepository, UserCreateDto, UserReadDto, User>, IUserService
     {
-        private readonly IStringLocalizer<Resource> _localizer;
-        public UserService(IUserRepository repository, IStringLocalizer<Resource> localizer, IMapper mapper) : base(repository, mapper)
+        private readonly IStringLocalizer<Resource>? _localizer;
+        public UserService(IUserRepository repository, IStringLocalizer<Resource>? localizer, IMapper mapper) : base(repository, mapper)
         {
             _localizer = localizer;
         }
@@ -49,7 +49,7 @@ namespace DigitalData.UserManager.Application.Services
             var user = _mapper.Map<User>(upDto);
 
             if (await HasEntity(user.Id))
-                return Result.Fail<int>().Message(_localizer[Key.UserAlreadyExists]);
+                return Result.Fail<int>().Message(_localizer?[Key.UserAlreadyExists].Value);
 
             //set the user
             var current_user = await GetUserAsync();
@@ -66,7 +66,7 @@ namespace DigitalData.UserManager.Application.Services
         {
             var user = await _repository.ReadByUsernameAsync(username);
             if (user is null)
-                return Result.Fail<UserReadDto>().Message(_localizer[Key.UserNotFoundInLocalDB]);
+                return Result.Fail<UserReadDto>().Message(_localizer?[Key.UserNotFoundInLocalDB].Value);
 
             var userDto = _mapper.Map<UserReadDto>(user);
             return Result.Success(userDto);