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

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.ThrowHelper.ThrowKeyNotFoundException()
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Dynamicweb.Security.UserManagement.VCard.GetVCard(String[] tags, IDataReader tagValues)
   at Dynamicweb.Security.UserManagement.VCard.GetVCard(String[] tags, User user)
   at Dynamicweb.UserManagement.Frontend.Frontend.DownloadVCard(String vCardFieldsString, User user)
   at Dynamicweb.UserManagement.Frontend.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)