If user receives this import error that means the mentioned HSN code is not present on NIC or IRP and hence throwing error as “Invalid HSN”.
User require to enter correct HSN code and reprocess the invoices for E-Way Bill or E invoice generation.
Step 1: Open e-way bill portal Step
Step 2: Go to 'Search'
Step 3: Select 'Product & Services'
Step 4: Enter HSN code or Name of product & Captcha
Step 5: Clicks 'Go'
Please go through the following link