Hi Everyone,

I am currently facing a critical issue after upgrading our Episerver CMS to version 12.26.1. The problem specifically lies with the menu provider, as we are consistently encountering 404 errors related to the new menu system while rendering from the add-ons section.

Steps to Reproduce:

1. Upgrade Episerver CMS to version 12.26.1.
2. Navigate to the created custom add-ons utilizing the menu system.
3. Observe the 404 error, indicating a failure in the menu provider.

Expected Behavior: We expect the menu system to function seamlessly without any 404 errors after the upgrade to Episerver CMS 12.26.1.

Additional Information:

• We have thoroughly reviewed the upgrade documentation to ensure all steps were followed accurately, may be possible we missed something.

Environment Details:

• Latest Episerver CMS Installed: 12.26.1
• Earlier Episerver CMS we are using: 12.13.2

Attachments: PFA

Thanks in advance for your help.