We set this up before taking it to the customer and yes this was a bit of a pain to adopt but eventually it did..
Took this to the customers site after having to reset and now this will not (after following everying) adopt in a Cloud controler that is hosted in Azure.. All the Switches and AP have come online but not the gateway
Originally logged in with the 192.168.0.1 address and registered to the cloud portal so that it appeared and clicking adopt... It failed
Then set the IP address on the 192.168.2.x range which the rest of the network is .. clicked adopt... failed
Looked through the logs on the controller and really vague..
All I get is
timeout-pool-0]  c.t.s.o.m.d.d.m.a.a(175): timeout wait adopt watch result of OmadacId(fc02b8e93074478f4fd4b56e59447085) DeviceMac() BusinessId(topic=smb_omada_business_fe6e7a70-bbe4-4edb-ace9-2743d17b0b3a, id=45613377-92e2-4f40-b257-2eafcfb25f2c), response:OperationResponse(errorCode=-39002, msg=Device adoption failed because the device does not respond to adopt commands., result=AdoptOneDeviceStatusResult(mac=, status=22, statusCategory=2))