RDP/VNC Error Codes
When connecting to remote desktops using RDP or VNC, you may encounter errors. This document lists common status codes and meanings for faster troubleshooting.
Status Codes
Next Terminal uses a unified numeric status-code system to represent success/failure states.
Success
0 (SUCCESS)
Operation completed successfully.
Unsupported Operation
256 (UNSUPPORTED)
Requested operation is not supported.
Server Errors
512 (SERVER_ERROR)
Internal server error. Operation cannot be completed.
513 (SERVER_BUSY)
Server is busy. Operation cannot be completed.
514 (UPSTREAM_TIMEOUT)
Upstream server did not respond in time (usually the remote desktop server).
515 (UPSTREAM_ERROR)
Upstream server returned an error (usually the remote desktop server).
Resource Errors
516 (RESOURCE_NOT_FOUND)
Related resource (file/stream etc.) was not found.
517 (RESOURCE_CONFLICT)
Resource is in use or locked.
518 (RESOURCE_CLOSED)
Related resource has been closed.
Upstream Connectivity Errors
519 (UPSTREAM_NOT_FOUND)
Upstream server does not exist or is unreachable.
520 (UPSTREAM_UNAVAILABLE)
Upstream server refused the connection.
Session Errors
521 (SESSION_CONFLICT)
Session ended due to conflict with another session.
522 (SESSION_TIMEOUT)
Session ended due to inactivity timeout.
523 (SESSION_CLOSED)
Session was forcibly closed.
Client Errors
768 (CLIENT_BAD_REQUEST)
Request parameters are invalid.
769 (CLIENT_UNAUTHORIZED)
Authorization denied because user is not authenticated.
771 (CLIENT_FORBIDDEN)
Permission denied. Logging in cannot resolve this.
776 (CLIENT_TIMEOUT)
Client response timeout (usually browser/user side).
781 (CLIENT_OVERRUN)
Client sent more data than protocol allows.
783 (CLIENT_BAD_TYPE)
Client sent unexpected/invalid data type.
797 (CLIENT_TOO_MANY)
Client has consumed too many resources.
Troubleshooting
Timeout issues
- 514, 522: check network and remote desktop server health
- 776: check client network, refresh and reconnect
Authentication issues
- 769: verify username/password
- 771: verify permission settings for remote desktop access
Server-side issues
- 519, 520: verify remote host address/port
- 513: retry later when server load is lower
Session conflicts
- 521: check whether same account is in use elsewhere
- 523: ask admin to check session management settings
If you encounter an unlisted code, contact the administrator and check server logs for details.