I'm not sure if we will be able to help with the Speedify issue, but we can look into the disconnected RUTX50 to check if it's experiencing any issues.
First, please make sure both devices are running the latest firmware. It can be downloaded here.
Could you clarify if you can reach the WebUI of the routers? Have you tried rebooting the problematic RUTX50 to check if anything changes?
Have you tried connecting to the problematic RUTX50 by WiFi?