It looks like the documentation isn’t completely up-to-date. The refresh token doesn’t need to be set on the SHC (bridge). It should be sufficient to set the authCode. The SHC bridge should then go online? Did you try adding the authCode and can you tell what happened?
After adding the code in the *.thing file, the bridge works fine (status: online), but after some time (hours), the bridge switch to error status, which is shown in Paper UI: OFFLINE - CONFIGURATION_ERROR - Cannot connect to innogy SmartHome service. Please set auth-code!
The auth-code is still within the *.thing file but in Paper UI the field of the SHC thing configuration is empty.
Within the logs I have several entries like:
2020-01-14 23:30:50.408 [DEBUG] [ery.InnogyBridgeDiscoveryParticipant] - Found innogy bridge via mDNS:SMARTHOME02 v4:[/192.168.XXX.XXX] v6:[/2002:xxx, /2002:xxx]
2020-01-14 23:30:50.423 [DEBUG] [ery.InnogyBridgeDiscoveryParticipant] - Found innogy bridge via mDNS:SMARTHOME02 v4:[/192.168.XXX.XXX] v6:[/2002:xxxxx, /2002:xxxx, /fe80:xxxx]