Appendix A: Troubleshooting

The OPC UA service's log messages can be found in the main ACM Log Viewer window. Filter on the source asiOPC_UA.

Issue	Possible Reason or Solution
The Server’s application certificate is not in the certificate store	The asiOpcUa service must be started at least once to create the self-signed certificate
Could not connect to Server: BadCommunicationError	ACM asiOpcUa service is not running
Could not connect to Server: BadServerHalted	ACM asiData service is not running
Browse on node ‘ns=2;s=MyNodeId’ failed with error “BadNodeIdUnknown”.	Items in a browse list may not exist in the namespace at the time of browsing. Data Variable nodes are only created in the address space when a client creates a monitored item for it. However, monitored items can be created from any item in the browse list.
The server does not support the configured security policy ‘http://opcfoundation.org/UA/SecurityPolicy#None’.	A client cannot connect a session using security policy ‘None’ unless the configuration option “Accept Non-Secure Sessions” is enabled.
Clients cannot write to items in the DataAccess namespace.	Writes to items by Anonymous users are not allowed unless the configuration option “Allow Writes to Items by Anonymous Users” is enabled.
Error "BadSecurityChecksFailed" was returned during OpenSecureChannel.	The client is not a trusted application. Import the client's public key certificate file into the OPC UA server's trusted peer store.
RegisterServer2 failed for at: opc.tcp://localhost:4840/. Exception=Error establishing a connection: BadNotConnected	The OPC UA Server is trying to connect to the local OPC UA Discovery Service, which is not running. Start the Discovery Service if there is one installed. If not, edit the OPC UA Server settings and un-check the property option "Register with Local Discovery Service", then restart the OPC UA Server service.