Required Zoho permissions
The Zoho permissions needed to sync products and customers
The "You don't have permission to perform this operation" message (error 403) is not related to your Order Invoicer subscription.
It depends on the Zoho user account used to connect Zoho — specifically its role inside the Zoho organization. If that role has no access to the Items, Contacts and Sales/Invoices modules, Zoho rejects our requests and the sync fails.
This error comes from Zoho, not from Order Invoicer. The OAuth authorization (the "scopes") is correct — it's the user's role inside Zoho that needs to be adjusted.
How to fix
Log in to Zoho Books with an Admin account.
Open Settings → Users & Roles → Users and find the user that connected Order Invoicer.
Check its Role. It must have full access (view + create) to the Items, Contacts/Customers and Sales/Invoices modules. You can adjust this under Settings → Users & Roles → Roles — either assign the Admin role, or enable those modules on its custom role.
Once the role is updated, reconnect Order Invoicer (or retry the sync).
A quicker alternative: reconnect Order Invoicer while logged in to Zoho as an Admin of the organization — that account already has all the required permissions.