Local rack startup problems on Ubuntu after update

Ubuntu version:
Docker version:
Docker version 18.09.1, build 4c52b90
Convox version:

I installed microk8s and went through this guide to ensure that there are no specific problems with kubernetes.
Then I dropped all containers I had running on the local rack, uninstalled and reinstalled it:

Installing rack: OK
Waiting for rack: timeout

Now in convox racks output I see the local rack running and I can switch on it, but all commands, including convox rack, fail with ERROR: Get https://convox.rack/system?: dial tcp: lookup rack.convox on no such host and other similar errors.

It looks like a dns problem, so I’ve 1)checked my (unchanged) dns conf both on the host and in /etc/docker/daemon.json 2)gone through ufw rules, but I’m still stuck.
Can anyone working with similar conditions chime in?

Where is the convox.rack hostname coming from? You do have CONVOX_HOST or RACK_URL set?

I have set neither (I’ve checked my .convox directory and env variables on the host machine).
The outcome is the same if I simply run convox test.

An update: we just tried repeating the process off our office network and everything seems to work, so it’s definitely a DNS problem (we have our own dns servers, all others are blocked including google’s).
Is there something that can be done about this in k8s?

Working with docker-compose we had similar problems and configured docker’s daemon.json with the IPs of our dns servers.