Hi @Royal!
This can happen due to temporary network instability, refreshing the page, switching tabs for a long time, VPN issues, browser extensions, or long-running executions. If the workflow continues running or completed successfully, then the issue was only a temporary UI disconnection. If it consistently fails with this message even for very simple workflows (for example, just a Set node), then it could indicate a broader connection issue, and contacting n8n Cloud support would be appropriate.
As a best practice, avoid relying on the active editor session for long-running workflows. Instead, trigger the workflow and monitor its progress through the Executions tab.