Cannot update Custom Metadata records from Subscriber org in managed app

Question

The custom fields are subscriber editable, and the custom metadata is not protected.

I can update the field values in developer org in a managed app, but when I try to update in subscriber org in the installed package I get the error:

Error retrieving metadata for entities of type: CustomMetadata. Error message: Custom metadata type VAT_Rate__mdt is not available in this organization.

But I can edit the record from the Setup in Salesforce

I am using the following code from the trail

Answer 1

For this to work in a subscriber org, you need to include the namespace on the custom metadata type portion of the record name. So if your package namespace is packns, you'd need (using the code you link to):

vatFullNames.add('packns__VAT_Rate.' + recordName)