We decided to upgrade our nopCommerce to a latest one.
So, as we have been using nopCommerce 3.50 and in order to avoid different kinds of errors during upgrading, we decided just to install a new version and import all categories, products etc. to a new site.
We have already imported about 300 products and it was importing fine with no erros.
But now (unexpectedly) it gives this error — "Object reference not set to an instance of an object."!
I have searched for some solution, but couldn't find what to do in this specific situation...
I have exported different categories of products from old site and tried to import each of them to the new site... In any event it gives the same error.
I went to the logs... and saw the following...
Log level
Error
Short message
Object reference not set to an instance of an object.
Full message
System.NullReferenceException: Object reference not set to an instance of an object. at Nop.Services.ExportImport.ImportManager.ImportCategoriesFromXlsx(Stream stream) at Nop.Admin.Controllers.CategoryController.ImportFromXlsx()
IP address
188.***.**.58
Customer [email protected]
Page URL
http://ali.ru/admin/category/importfromxlsx
Referrer URL
/admin/category/list
Created on
6/9/2017 4:42:49 AM
So, how to fix it? What to do in order to get rid of these errors?
Thanks for your help in advance!