Error -356500 When Starting OPC UA Server

Updated Dec 22, 2023

Reported In


  • LabVIEW OPC UA Toolkit

Issue Details

When I try to deploy an OPC UA Server on my Windows host machine, by utilizing the Start VI from the LabVIEW OPC UA Toolkit, I always get the following error:

Error -356500 occurred at NI OPC UA

Possible reason(s):

OPC UA Toolkit: (Hex 0xFFFA8F6C) An internal error occurred as a result of a programming or configuration error. 

This error is shown in the dialog box shown below:

Error -356500 OPC UA Toolkit
The system has the correct licenses and initializes an OPC session correctly. Additionally, the OPC UA default port (49580) has been configured as inbound/outbound exclusions on my firewall. 


To solve the issue, just modify the port you are utilizing for the OPC UA Server. Port 49580 is the default one, but it can be modified on the TCP port input of the OPC UA Server Create VI. You may need to verify first which ports are open before you define a different one for the OPC UA Server that is not being used by another process. To do so, when utilizing a Windows host machine, you can follow the procedure described in this link.

Additional Information

This error is showing up because TCP port 49580 is already being used by another process. That is the reason why utilizing a different one can solve the issue.