@solidf 

I am running exactly the same setup...5.9.9 in Docker on my 1522+.  Worked flawlessly.  I used host networking not bridged though.  If you bridged the container you should add a default LAN route for 172.17.0.0/16 or whatever the Docker private network is via your NAS's IP on your LAN subnet.

  @solidf 

You have previously 'registered' the desired gmail address with the TPlink cloud service?  You have verified you can login into the cloud service via the web?

  @solidf 

No, don't detach your OC200.

I actually have several docker controllers on the same NAS that are cloud connected.  The active one is 'host' networked, and the test versions are 'bridged' to avoidi port conflicts.  All were registered with the same gmail and password.

The only port forward I have is to forward my WAN port 8043 to the NAS port 8043, but this shouldn't be necessary as the my OC200 has no such route, it only has the discovery ports (29810-29814) forwarded, but not the 8043.

  @solidf 

Have you tried using the mobile app via a cellular connection...ie with no wif enabled?  I'm wondering if there's something funky with your provider pipe?

  @solidf 

Step 1: gain access to cloud service independently

This proves that the gmail account you are using is registered, valid and working as your cloud account

Step 2: figure out why the above gmail account is failing to connect from your local controller when you try to bind it to the cloud.

So my ask earlier was if you can log into the TPlink website by browser or the mobile app.