Comment 5 for bug 1754061

The error from Zaqar is totally expected. You can't claim messages from a queue that doesn't exist. We should either check the existence of the queue or create it inconditionally in the workflow.

That said; there is no reason for this to fail the deployment. The 503 happens (as expected) on working CI runs. Either this is noise, and it just shows that error for some reasons, or something checks wrongly that workflow for success (randomly?).