Getting contentLength -1 in both begin and progress callbacks

In **begin callback** getting this response
```
{"contentLength": -1, "headers": {"Accept-Ranges": "bytes", "Connection": "Keep-Alive", "Content-Encoding": "gzip",
"Content-Type": "audio/mp4", "Date": "Thu, 23 Sep 2021 13:30:29 GMT", "Keep-Alive": "timeout=5, max=100", "Last
Modified": "Tue, 14 Sep 2021 07:51:37 GMT", "Server": "Apache", "Transfer-Encoding": "Identity", "Vary": "Accept
Encoding,User-Agent"}, "jobId": 1, "statusCode": 200}
```

and in **progress callback** getting
```
{"bytesWritten": 4762239, "contentLength": -1, "jobId": 1}
```

Now, I can't calculate the progress, what's going on here? why I'm getting **contentLength** is -1