I ran into an issue when using this to check a friend's status. Handle is: inkstain.neocities.org
The request is a GET to https://inkstain.neocities.org/.well-known/atproto-did. My devtools say: "Response body is not available to scripts (Reason: CORS Missing Allow Origin)". The file otherwise exists, and is accessible via a separate HTTP request.
Accessing .well-known/atproto-did for another account on a mushroom PDS seems to work just fine. For my own account, it fails as expected because I only have a DNS record set.