An error occured while attaching module (Dynamicweb.Frontend.Content)

System.ArgumentNullException: Value cannot be null.
Parameter name: value
   at System.Xml.Linq.XAttribute..ctor(XName name, Object value)
   at NLWI.Connector.NavByManager.ContractImplementations.Base.ANavService.d__11.MoveNext() in D:\TFS\N-LWI\Main\src\NLWI.Connector.NavByManager\ContractImplementations\Base\ANavService.cs:line 168
   at System.Xml.Linq.XContainer.AddContentSkipNotify(Object content)
   at System.Xml.Linq.XContainer.AddContentSkipNotify(Object content)
   at System.Xml.Linq.XElement..ctor(XName name, Object[] content)
   at NLWI.Connector.NavByManager.Services.OrderSearchConnectorContract.Download(IDownloadOrderParameters parameters) in D:\TFS\N-LWI\Main\src\NLWI.Connector.NavByManager\ContractImplementations\SelfService\OrderSearchConnectorContract.cs:line 159
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at NLWI.Core.Connector.Expressions.MethodAnalyser.<>c__DisplayClass2_0`2.b__0()
   at NLWI.Core.Connector.Logging.NLogMethodLogging.<>c__DisplayClass9_0`1.b__0()
   at NLWI.Core.Connector.Proxy.ServiceProxy`1.Invoke[TResult](Expression`1 method, Func`1 cacheDependencyBuilder)
   at NLWI.Core.Connector.Proxy.ServiceProxy`1.Invoke[TResult](Expression`1 method)
   at NLWI.Platforms.Dynamicweb8.CustomModules.NLWI_SelfService.Repositories.SelfServiceRepository.DownloadDocument(IDownloadOrderParameters downloadOrderParameters)
   at NLWI.Platforms.Dynamicweb8.CustomModules.NLWI_SelfService.NLWISelfServiceContentModule.GetContent()
   at Dynamicweb.Frontend.Content.GetModule(DataRow& ParagraphRow)