AccessDenied for https://download-files.appdynamics.com/S3

I tried to download Java8 21.6.0, but failed like following.

```
$ ./get-agent.sh download java8 -v 21.6.0 --dryrun
ERROR: Could not download your request java8. Check the download page to ensure the agent type and version exist
https://download-files.appdynamics.com/S3 path:
processed payload :
https://download.appdynamics.com responded with unexpected reponse. Please ensure you have connectivity to the download page
===========Begin content============
{"count":0,"next":null,"previous":null,"results":[]}===========End content============
```

Now we cannot access to https://download-files.appdynamics.com/S3. Could you please take a look at this issue.

Thanks

Start by running the reported command in get-agent.sh with Java8 version 21.6.0 and inspect the request to https://download.appdynamics.com and the S3 path. Compare the empty API response and access failure with the download page behavior; done means identifying and resolving the cause of the failed download or documenting why the requested agent is unavailable.

Written by the indexing model from the issue text.