try another way to implement the data stucture

UserService.DatabaseLayer/DataModels/ConnectionStringSettings.cs

@@ -0,0 +1,12 @@
+using LinqToDB.Configuration;
+
+namespace UserService.DatabaseLayer.DataModels
+{
+    public class ConnectionStringSettings : IConnectionStringSettings
+    {
+        public string ConnectionString { get; } = @"Server=srvbo;Database=UserService2;Uid=UserDbAdmin;Pwd=12345678;";
+        public string Name { get; } = "UserServiceDb";
+        public string ProviderName { get; } = "MySqlServer";
+        public bool IsGlobal { get; }
+    }
+}