@MR.S something I noticed while recreating a new site is, that the adoption process of the router takes pretty much forever, like 2-5 minutes, the ER7412-M2 was way quicker than that, like started to...

@MR.S good point, I may try setting my side up again because the direct connection to my synology also worked without any disconnects.. Maybe there is something broken with the big gap between the 2...

I mean the thing I don’t get is the ER7412-M2 works perfectly fine too on that configuration. The same connection path as the ER8411 Gateway -SFP- SG3428X-M2 -RJ45- Synology The controller is running...

@MR.S Okay, good point will try that, I actually have two sides, but since the external side is anyways connected over a VPN with a DynDNS address that's fine not having there an address. The weird...

yes, it is enabled. I stopped the controller now for 15 hours or something and now I started it up again and disabled DNS Proxy and DNS Cache until now I couldn't see any re-adoption again. I'm not...

@Clive_A I don't get why too, but could be that it was just I had luck because now it does the heartbeat lost process "only" after like 30-50 Minutes and no more all 5 or even less