Apple-app-site association file is not fetching from the server

Thanks for the post. A quick check to verify, I made a request to get the file and it seems like there is an error in one of the values inside the file itself. Please, note the error "invalid character '\u003c' looking for beginning of value”

Thanks for sharing a link to the file. I was able to make a request to review it and encountered an error that might be preventing its processing. The file seems to have an invalid character '\u003c' (less-than symbol) at the beginning of one of its values. This character might cause issues. Could you check the file and try to resolve this? Perhaps it's an encoding problem. Note the error "invalid character '\u003c' looking for beginning of value”

curl -D /dev/stderr -s 'https://app-site-association.cdn-apple.com/a/v1/mobile.plymouthrock.com' | head
HTTP/1.1 404 Not Found
Apple-Failure-Details: {"cause":"invalid character '\u003c' looking for beginning of value"}
Apple-Failure-Reason: SWCERR00401 Bad JSON content
Apple-From: https://mobile.plymouthrock.com/.well-known/apple-app-site-association
Apple-Try-Direct: false
Cache-Control: max-age=3600,public
Content-Length: 10
Content-Type: text/plain; charset=utf-8
Date: Thu, 20 Jun 2024 15:19:48 GMT
Expires: Thu, 20 Jun 2024 15:19:58 GMT
Age: 2807
Via: http/1.1 ussjc2-vp-vst-011.ts.apple.com (acdn/153.14426), https/1.1 ussjc2-vp-vfe-005.ts.apple.com (acdn/153.14426), http/1.1 ussjc2-edge-lx-002.ts.apple.com (acdn/22.14426), http/1.1 ussjc2-edge-bx-006.ts.apple.com (acdn/22.14426)
X-Cache: hit-fresh, hit-stale, hit-fresh, hit-fresh
CDNUUID: aae95d55-46ae-4e07-b1d8-4ce86890d4d7-5373912411
Connection: keep-alive

Please verify the format of your AASA file. It should contain either an Array of appIDs or an Array of components. How to verity your AASA file, where you can find a sample recommended format: https://developer.apple.com/documentation/technotes/tn3155-debugging-universal-links

I recommend referring to the Tech Note for instructions on how to verify the file's format using the command 'sudo swcutil verify'. It's a comprehensive resource that will also guide you through setting up the file correctly. Please, feel free to share your file here so I can provide further recommendations and suggestions. I hope this helps resolve the issue.

Also, the error with “ \u003c” means “<,” is an HTML tag. That means your server is returning HTML instead of JSON, which could be due to the User-Agent header sent by the proxy: the site is interpreting this as an unsupported browser. Consequently, the server needs to ensure that it accepts traffic from user-agents of the form AASA-Bot/*.

To fix the issue, your hosted server needs to accept traffic from user-agents of the form AASA-Bot/*. Please let me know if that resolves the problem.