Hi @anfonse,

If you can still log into the OC200, you may backup the settings files first and go to Device list to forget all devices, all device will be back to the Standalone mode.

But if you can not log into the controller, then there is no choice but to reset all devices hardwired containing the OC200.

And certainly, the network will be down after you reset the ER7206.

  @anfonse 

If this was my 'problem', I would take the OC200 and factory default it.  I would then re-configure my network in the OC200, ie create the WAN, LAN, etc settings and ignore all the 'Managed by Other' messages.  I would then at a time outside of business hours, factory default the 7206 and then re-adopt it.  Assuming you created the same subnets mapped to the same ports, it should just come back up.  You can then fine tune things, like add reservied IPs, or configure ACLs as needed.  Once up and running, immediately perform a full backup!

The Omada routers should free-wheel without an active controller.  The only thing having the controller non-functional will do is break things like meshed APs, or fast-roaming on capable APs.