Troubleshooting > UA Gateway Event Log Messages
UA Gateway Event Log Messages
The following information concerns messages posted to the Event Log.
Consult the help on filtering and sorting the Event Log. The type of message (informational, warning) and troubleshooting information is provided whenever possible.
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In UA support, access to session diagnostics is only available for sessions using sign and encrypt. UA sysadmin role can see all subscriptions (see https://github.com/OPCFoundation/UA-.NETStandard/issues/1993).
Created session with downstream server. | Endpoint URL = <Endpoint URL>.
Error Type:
Information
Possible Cause:
Connection established with downstream server.
Failure while establishing session with downstream server. | Endpoint URL = <Endpoint URL>, Status code = <Status code>, Description = <Description>.
Error Type:
Error
Possible Cause:
Refer to the OPC status code and description for cause.
Possible Solution:
The solution depends on the OPC UA status code.
Reconnecting session with downstream server. | Endpoint URL = <Endpoint URL>.
Error Type:
Warning
Possible Cause:
Connection with downstream server has dropped.
Possible Solution:
1. Make sure the downstream server is reachable by UA Gateway.
2. Make sure the client interface configuration for the downstream server is correct.
Closed session with downstream server. | Endpoint URL = <Endpoint URL>.
Error Type:
Information
Possible Cause:
Connection with downstream server has been closed.
Cannot communicate with OPC UA gateway service. Port collision on UA gateway outbound port. Port is already in use. | Port = <Port Number>.
Error Type:
Information
Possible Cause:
Port being used for ua_gateway.UA Gateway_PLUGIN_IPC_PORT setting and needs to be configured to one not in use.
 
Possible Solution:
Performing the following PUT request with a new port number that is not in use.
Endpoint PUT
{{host}}:{{port}}/config/v1/project/_ua_gateway
Message body:
{
"PROJECT_ID": <project-id-number>,
"ua_gateway.UAG_PLUGIN_IPC_PORT": <desired-port-value>,
}
where the project ID is acquired by performing a GET on the same endpoint.
The Application Instance Certificate is invalid and needs to be updated (UA clients must trust the new certificate to connect). | Status code = <Status code>, Description = <Description>.
Error Type:
Error / Warning
Possible Cause (Error):
The UA Gateway application instance certificate is invalid (but not corrupt). Potential reasons: invalid private key, application URL is empty, key size is too small (2048 minimum), missing thumbprint, subject is missing / incorrect, or certificate expired or not yet valid.
Possible Cause (Warning):
The self-signed or CA issued UA Gateway application instance certificate has expired or is not yet valid, certificate host name is invalid, or unable to determine if the self-signed or CA issued certificate has been revoked.
Possible Solution:
Generate a new application instance certificate.
An invalid server endpoint has failed on server interface start. | Status code = <Status code>, Description = <Description>.
Error Type:
Error
Possible Cause:
This can be caused by a port collision, attempting to connect to an invalid port, an invalid IP address, invalid machine name, or unsupported / invalid protocol.
Possible Solution:
Resolve the issue and send a valid server endpoint to the UA Gateway for recovery.
Startup failed. Port collision on UA Gateway inbound port : <Port number>.
Error Type:
Error
Possible Cause:
Another application is using the same port number.
Possible Solution:
Quit the application using this port number or choose a different port number for UA Gateway.
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Tip:
Endpoint PUT
{{host}}:{{port}}/config/v1/project/_ua_gateway
Message body:
{
"PROJECT_ID": <project-id-number>,
"ua_gateway.UAG_PLUGIN_IPC_PORT": <desired-port-value>,
"ua_gateway.UAG_SERVER_IPC_PORT": <desired-port-value>,
}
Failed to add subscription for device | Endpoint URL = <Endpoint URL>, Status Code = <Status Code>, Description = <Description>.
Error Type:
Warning
Possible Cause:
The server connected to the client interface has reached its maximum subscription count; a new subscription to this server cannot be created on the client interface.
Possible Solution:
To establish a subscription to this server, other subscriptions must be removed on the server. This is external to the Kepware UA Gateway.
Client established a session with the server interface. | Client Application URL = <Application URL>.
Error Type:
Information
Possible Cause:
A client established a connection with the configured server interface.
Using .NET CLR Version = <Version>.
Error Type:
Information
Possible Cause:
Logged at initialization to report the .NET Common Language Runtime being used by the UA Gateway.
Failed to install the UA Gateway service. System requirements are not satisfied.
Error Type:
Error
Possible Cause:
The required version of .NET is not installed on the system.
Possible Solution:
Install the required version of .NET according to the UA Gateway installation requirements.
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