Hello,
I will ask you to replicate the issue, then on both RUTX50 and RUTX10 navigate to System → Administration → Troubleshoot and generate troubleshoot files. These files can be attached to the original post and will only be visible to Teltonika moderators. They will provide me with the logs and your configuration to check what could be the issue. As for the WebUI, on the RUTX10, change the firewall zone of the mesh network to LAN. This way the WebUI of the router should be accessible from the RUTX10.
Best regards,
DaumantasG