An exception of type 'Microsoft.CommerceServer.Catalog.ValidationException' occurred and was caught Commerce server

This error occurred when catalog name is null or empty 

To fix  This follow these steps 

1.       Find sessionstate tag in  the web.config 

By default it is 20 min increase to 60 min (Depends on requirement )

  timeout=”60”/>

2.       If your maintaining catalog name in session level  .Provide default catalog name if session expire

 Ex :

 public string SessionCatalogName

        {

            get

            {

                if (HttpContext.Current.Session[APConstants.SessionVariables.CatalogName] != null)

                {

                    return HttpContext.Current.Session[APConstants.SessionVariables.CatalogName].ToString();

                }

                else

                {      return APConstants.ApplicationParameters.GKDefaultCatalogName;

                }

            }

            set

            {

                HttpContext.Current.Session[ApConstants.SessionVariables.CatalogName] = value;

            }

        }