Scheduler in Environments crashed after RancherServer Crash

I had a strange thing with my RancherServer 1.4.2 environments. I know that I am not running the latest version, but I would like to understand what happend.

I have a RancherServer 1.4.2 serving multiple environments. One day the master crashed due to a problem with the VM it was running on.
No Problem, containers on the nodes kept running and all was fine.

I fixed the master and since then all Schedulers in the Network Stacks of the Environments wouldnt start. Which resulted in containers not starting after a change.
Only a restart of the Docker Daemons on the nodes solved the problem.

Any idea why the schedulers would crash, if the master vanishes?
I never saw this behavior before when I stopped the master on purpose.

Thanks, Chris

Did the IP address of the master change? That could have done it potentially. Did the logs of scheudler container indicate why it was crashing?

No, IP is the same.

But I see errors in RancherServer, which I didnt recognize before:

2017-11-16 16:11:59,667 ERROR [:] [] [] [] [torService-1457] [.e.s.i.ProcessInstanceDispatcherImpl] Unknown exception running process [instance.create:4116214] on [156662] io.cattle.platform.util.exception.ExecutionException: Failed to find network for networkMode appl_default
        at io.cattle.platform.docker.process.instance.DockerInstancePreCreate.handle( ~[cattle-docker-compute-0.5.0-SNAPSHOT.jar:na]

And I have no idea, what networkMode appl_default means.