Yet another cause: if your namespace has a hyphen ("-"), then it will build and run correctly, but the resource won't be accessible. Namespaces (identifiers) aren't supposed to have hyphens, but this doesn't appear to be enforced anywhere except in loading resources. This has burned me twice over the decade.

Yet another cause: if your namespace has a hyphen ("-"), then it will build and run correctly, but the resource won't be accessible. Namespaces (identifiers) aren't supposed to have hyphens, but this doesn't appear to be enforced anywhere except in loading resources. This has burned me twice over the decade.