@zegor_mjol, I just tried your setup just now, and have no issues getting either device to connect to a 580. I did set this all up manually, so its technically P2P, not a hub scenario. Also I have manually set the ports to sequential numbers (ie: HD2:4707, Transit:4708, and because its a SF device behind a SF device the handshake port is different 33015).
For testing - first try I just did a HD2 tunnel, second time was a Transit tunnel and HD2 tunnel, third was both tunnels, and fourth was disabling cellular on HD2 leaving only WAN1 up. Every time there was no issue with the tunnel dropping.
- Try switching to a P2P/Star setup over a Hub setup, you can click the advanced options and add an extra device. This might help, I didn’t test this, as all my SF’s are manual and programming through IC2 overwrites the current setup.
After searching forums, this is really all I could find regarding a “link failure” mainly pointing to a port issue. Not available - link failure, no data received