The 404 page error for your "Cancel Subscription" link in Odoo 17 newsletter indicates a broken configuration. Here are a few ways to resolve it:

1. Verify the Link Configuration:

• Check the Link URL:
  • Locate the "Cancel Subscription" link in your newsletter template.
  • Ensure the URL points to the correct unsubscribe controller and action in Odoo.
  • Verify it starts with your Odoo website URL followed by the correct path (e.g., /web/unsubscribe).
• Test the Link:
  • Use a link checker tool or manually open the link in a new browser tab.
  • Ensure it leads to the intended unsubscribe page within Odoo, not a 404 page.

2. Check Unsubscribe Functionality:

• Open the Unsubscribe Page:
  • Access the unsubscribe page directly through your Odoo backend.
  • Navigate to Marketing > Mail Marketing > Mail Marketing Lists.
  • Select the relevant list and click on the "Lists & Subscribers" tab.
  • Click on the "Unsubscribe" button.
• Test Unsubscribe Process:
  • Use a test email address to subscribe to your newsletter.
  • Click on the "Cancel Subscription" link from the newsletter.
  • Ensure the unsubscribe process works correctly and removes the email from the list.