How get more info for HLS stream troubleshooting

Sometimes my HLS stream fails while playing on my Roku. I'm using "roVideoPlayerEvent" isRequestFailed() to detect the problem and get spam of events:

ERROR CODE: -1
ERROR MESSAGE: "There was an error in the HTTP response.  This could mean that malformed HTTP headers or an HTTP error code was returned."

or sometimes

ERROR CODE: -3
ERROR MESSAGE: "An unexpected problem (but not server timeout or HTTP error) has been detected."

I can't correctly understand what does it mean, what is happened? 
Can I get more info about trouble?

Thx for any help!