ThingsBoard Server-Side RPC Issue: no_active_connection Error After Device is Online for a Few Weeks

Question

I’m experiencing an issue with ThingsBoard regarding server-side RPC for a NodeMCU ESP8266 device. The RPC initially works perfectly, but after a few weeks, I encounter the following error:

Error: no_active_connection enter image description here HTTP Status Code: 409 enter image description here

About any details:

• About connection: The device is sending telemetry data to ThingsBoard without any issues, indicating it is online and properly connected
• RPC request format: curl -v -X POST -d @set-request.json https://$ADDRESS/api/plugins/rpc/oneway/$DEVICE_ID --header "Content-Type:application/json" --header "X-Authorization: Bearer $JWT_TOKEN"

What I've tried:

• Device Connectivity: I have verified that the device is still online and sending telemetry data consistently to ThingsBoard.
• Access Token: The device access token has not changed, and there are no network issues.
• Recreating Device: Deleting and recreating the device in ThingsBoard temporarily solves the issue (RPC works again), but after a few days/weeks, the same error reappears.

Questions:

1. Has anyone experienced similar issues with server-side RPC after a device has been online for an extended period?
2. What could be causing this no_active_connection error when the device is still actively sending telemetry data?
3. Could the Refresh Token Expiration Time setting in ThingsBoard (sysadmin) impact RPC operations or device connections in any way, even though the device uses static access tokens?

Any insights or suggestions on what might be causing this issue or how to resolve it would be greatly appreciated!

Thank you!