Object does not exist message after adding device to an application

Hello!
I tried to install LoRa server on Ubuntu 18.04 machine, and everything went OK. I followed the instructions on https://www.loraserver.io/guides/debian-ubuntu/ and finished the installation. I kept the default settings, I only had to change dsn for my databases.
Then, at the point I added a new OTAA device for my application, I got a message Object does not exist (code: 5). Does anyone know what is happening here, and how to resolve this problem?
Please keep in mind I just created a device in LoRa App server, and right away I received an error message like shown in screenshot attached. I have not even reached the point where I try to activate my device.
Screenshot%20from%202019-09-04%2016-39-35|690x388

It is a bug: https://github.com/brocaar/lora-app-server/issues/359.