Resolving EADDRINUSE Errors in OpenClaw Voice-Call

What's Happening\n\nYou are seeing an EADDRINUSE error when initiating calls, even though your webhook server appears to be running on the expected port (e.g., 4444). This indicates that the voice-call plugin is attempting to bind a new server instance to the same port that is already in use, instead of utilizing the existing gateway connection.\n\n## The Fix\n\nThe most reliable solution is to upgrade to the latest stable release of OpenClaw. This issue was specifically addressed in PR #32391, which ensures that failed runtime promises are properly cleared from memory.\n\nIf you cannot update immediately, you must ensure that your environment completely clears the hung state. Since SIGUSR1 reloads often fail to release the port, a full process restart is required:\n\n1. Stop the OpenClaw service: systemctl stop openclaw\n2. Verify no lingering processes are holding the port: lsof -i :4444\n3. Kill any remaining processes: kill -9 <PID>\n4. Start the service: systemctl start openclaw\n\n## Why This Occurs\n\nThe root of the problem lies in the ensureRuntime() function within the plugin. When the initial webhook server setup fails, the code sets a runtimePromise but fails to clear it when the runtime remains null. Future calls to voice_call then attempt to await this stale, failed promise, leading to redundant binding attempts that trigger the address-in-use conflict.\n\n## Prevention\n\nAvoid relying on hot-reloads when debugging plugin configuration changes. If you modify your Twilio provider or webhook settings, always perform a full service restart rather than a signal-based reload. This prevents the race condition between the old process releasing the port and the new process attempting to bind to it.

Last Updated: March 2026