Troubleshooting

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Troubleshooting

This chapter lists the most common problems and how to diagnose them. The first stop for any issue is the log panel and the application log file, whose folder can be opened from the UI.

Cannot connect to a server

• Wrong URL or unreachable host. Confirm the endpoint URL (opc.tcp://host:port) and that the server is running and reachable.
• Security policy mismatch. The client's selected security policy must be one the server offers. Try None first to isolate a security problem.
• Certificate not trusted. With signing/encryption, the two sides must trust each other's certificates. Check the PKI store (see Configuration).
• Identity rejected. Anonymous access may be disabled, or the username/password may be wrong.

Many servers, for example PLC panels, report their own host name such as opc.tcp://AOPT690:4840. The client always keeps using the address it actually reached, so entering the IP address is enough. If you enter a host name that this PC cannot resolve, the error message says so; enter the server's IP address instead or use Scan network….

Values do not update

• Confirm the variable is actually subscribed (not just read once).
• Check the variable's access level — some nodes are read-only.
• For a designed server, confirm the variable has a simulation if you expect it to change on its own (see OPC UA Server).

The local server does not start

• Runtime not found. The headless OpcUaServerRuntime executable must sit next to the application; a broken deployment is the usual cause.
• Port already in use. Another server may hold the configured port; change the endpoint port.
• Invalid project. The validator reports problems (for example a node that references a namespace the project does not declare) before the server starts.
• Crash on start. The controller reports a crash and the runtime's output is captured in the log; restart or kill and retry.

Configuration or data problems

• Settings not persisting. Confirm whether the app is running installed or portable and that the writable data location is accessible (see Configuration).
• Corrupt project file. Projects are written atomically, but an externally edited .uaproj / .uaserver may fail to load; the loader reports a typed error.

Collecting diagnostics

When reporting a problem, include the application version (see About and Version Information) and the relevant section of the log file.