Problem in Stock

Hi! I am new in Erpnext. I am trying to set it up. Problem in stock section " You cannot see that page" when I choose Item. Probably I changed something without to customization. Any ideas?

Check your user roles. - YouTube

Thank you a lot for the help. May I ask you another thing? If no, reply
no and I will get in community.

I have set prices in items (default price list)
I know how to set discount rate or special price for each customer
(pricing rule) for each item or category.
QUESTIONs:
Is there any way to have all the default price list (for all the
products), then copy and add discount or special price and not to do
that product by product for a specific customer?
Is there any way to have the above special price list (price and
discount) for each customer as a report?

Thank you in advance

Nikoletta

@CandyCo See Pricing Rule: https://frappe.github.io/erpnext/user/manual/en/accounts/articles/pricing-rule.html

Also best to start a new topic for a new question.