In the Status report of the Streaming Client firmware you can find the "Last Error".
Here is the full list of errors:
0 = "No Error"
1 = "DNS Resolution Problem"
2 = "No TCP Response"
4 = "No HTTP Response"
5 = "Invalid Response"
6 = "Missing Path"
7 = "Missing Port Number"
8 = "Missing Hostname"
9 = "Invalid Filetype"
10 = "Filesystem Error"
11 = "Connection Timed Out"
12 = "Invalid Protocol"
13 = "Too Many Dropouts"
14 = "Invalid Port"
15 = "URL Syntax Error"
16 = "Playlist Error");
18 = "Bad MMS Response"
19 = "Audio Format Not Supported"
20 = "HTTP Redirect Not Supported"
21 = "Too Many Redirects"
22 = "Wrong HTTP Redirect"
99 = "Internal Error"
400 = "HTTP Bad Request"
401 = "HTTP Unauthorized"
402 = "HTTP Payment Required"
403 = "HTTP Forbidden"
404 = "HTTP Not Found"
405 = "HTTP Method Not Allowed"
406 = "HTTP Not Acceptable"
407 = "HTTP Proxy Authentication Required"
408 = "HTTP Request Time Out"
409 = "HTTP Conflict"
410 = "HTTP Gone"
411 = "HTTP Length Required"
412 = "HTTP Precondition Failed"
413 = "HTTP Request Entity Too Large"
414 = "HTTP Request URL Too Large"
415 = "HTTP Unsupported Media Type"
500 = "HTTP Server Error"
501 = "HTTP Not Implemented"
502 = "HTTP Bad Gateway"
503 = "HTTP Out of Resources"
504 = "HTTP Gateway Time Out"
505 = "HTTP Version not supported"
There are error for the USB, for the playlists, for the network connectivity or for HTTP.