Error Codes

Risuko uses numeric error codes to identify download failures. Each error code belongs to a category based on its numeric range.

When a download fails, the error code and a human-readable message are stored on the task and displayed in the UI.

Error Code Ranges

Range	Category
1xx	General errors
2xx	Network errors
3xx	HTTP errors
4xx	File system errors
5xx	Protocol-specific errors
6xx	Resource errors
9xx	Internal engine errors

General Errors (1xx)

Code	Name	Description
100	Unknown	An unclassified error occurred. Check the error message for details.
101	Cancelled	The download was cancelled by the user or system.
102	Checksum Mismatch	The downloaded file's checksum does not match the expected value.

Network Errors (2xx)

Code	Name	Description
200	DNS Resolution Failed	Could not resolve the hostname. Verify the URL and your DNS settings.
201	Connection Refused	The remote server refused the connection. The server may be down or the port may be blocked.
202	Connection Reset	The connection was reset by the remote host during transfer.
203	Connection Timeout	The connection timed out before a response was received.
204	Network Unreachable	No network route to the host. Check your internet connection.
205	TLS Handshake Failed	SSL/TLS negotiation failed. The server's certificate may be invalid or the TLS version unsupported.
206	Proxy Connection Failed	Could not connect through the configured proxy server.

HTTP Errors (3xx)

Code	Name	Description
300	Unauthorized	HTTP 401 — The server requires authentication credentials.
301	Forbidden	HTTP 403 — Access to the resource is denied.
302	Not Found	HTTP 404 — The requested file does not exist on the server.
303	Range Not Satisfiable	HTTP 416 — The server cannot fulfill the byte range request. The file may have changed.
304	Too Many Requests	HTTP 429 — Rate limited by the server. Try again later.
305	Server Error	HTTP 5xx — An error occurred on the server side.
306	Service Unavailable	HTTP 503 — The server is temporarily unavailable.
307	Redirect Loop	Too many HTTP redirects were followed.
308	Response Error	An unspecified HTTP response error.

File System Errors (4xx)

Code	Name	Description
400	Disk Full	No space left on the target disk or storage quota exceeded.
401	Permission Denied	Insufficient permissions to write to the download directory.
402	File Not Found	A required local file (e.g., a partial download) was not found.
403	File Already Exists	The output file already exists and overwrite is not enabled.
404	Invalid Path	The output file path is invalid or contains unsupported characters.
405	I/O Error	A general file system I/O error occurred.

Protocol-Specific Errors (5xx)

BitTorrent

Code	Name	Description
500	Metadata Failed	Failed to resolve torrent metadata from peers or trackers.
501	No Seeds	No seeders are available for this torrent.
502	Invalid Torrent File	The `.torrent` file is corrupt or not a valid BitTorrent metainfo file.

ED2K

Code	Name	Description
510	Server Unreachable	Could not connect to the ED2K server.
511	File Not Found	The file was not found on the ED2K network.

M3U8 / HLS

Code	Name	Description
520	Parse Failed	Failed to parse the M3U8 playlist. The URL may not point to a valid HLS stream.
521	Segment Failed	One or more video segments failed to download.
522	Decrypt Failed	Failed to decrypt an encrypted HLS segment (AES-128).

FTP / SFTP

Code	Name	Description
530	FTP Login Failed	Authentication failed. Check your username and password.
531	FTP File Not Found	The file does not exist on the FTP server.
532	FTP Transfer Failed	The file transfer was interrupted or failed.
533	SFTP Auth Failed	SFTP authentication failed. Check your credentials or private key.
534	SFTP Host Key Failed	The SFTP server's host key could not be verified.

Resource Errors (6xx)

Code	Name	Description
600	Out of Memory	The system ran out of memory during the download.
601	Too Many Connections	The maximum number of concurrent connections was exceeded.

Internal Errors (9xx)

Code	Name	Description
900	Engine Not Running	The download engine is not running. Try restarting the application.
901	Invalid Parameter	An invalid parameter was passed to the engine.
902	Session Corrupt	The session data file is corrupt and could not be loaded.

Troubleshooting

Common Fixes

2xx Network errors: Check your internet connection, firewall, and DNS settings.
3xx HTTP errors: Verify the download URL is correct and accessible in a browser.
4xx File system errors: Ensure the download directory exists and has write permissions.
5xx Protocol errors: Check protocol-specific settings (trackers, credentials, etc.).

For detailed error information, check the application log files. The log directory is shown under Preferences > Advanced > App log path. Log files are rotated daily and named risuko.log.YYYY-MM-DD.