Why does Azure give me an intermittent Error 503. The service is unavailable?

Question

I have an Azure service that has been running for a long period of time. It builds a word or powerpoint document based on arguments in the request and returns a uri to the

Answer 1

For me the error went away when I set up auto-scaling. I think failover requests were getting routed to my second VM, and the second VM took some time to spin up because it wasn't ready for the activity. Auto-scaling shut down my second VM and the error no longer appears (I'm assuming it will spin up if/when I get enough traffic to use it).

Hope this also helps someone.