A few times now we have encountered a bug in the Gateway on the OPC Connections page. Sometimes it will just show a blank white screen, and an error modal in the top right will appear stating “Route Concurrency Limit Reached”, or something similar. The screen will occasionally re-render and show a flash of the normal page, but it shows a dialog to add a new OPC connection as if our existing OPC connections aren’t there. The only fix we’ve found has been rebooting the server the gateway is on or restarting the gateway via gwcmd -r.
We’re not sure what causes this error to happen, but it seems to happen when editing OPC settings (could be a bias due to noticing it when editing these settings). The latest time it happened I was updating an OPC connection via the endpoint configuration page, and the changes failed after I clicked Update and then I started seeing this error.