Why am I getting "ERROR: 503 Service Unavailable"?

Generally speaking, a 50* (500, 503, etc) error means that the targetted server (in the case of Jesse it's usually the exchange) is not available.

Examples of reasons could be:

• The exchange is in maintenance
• or the exchange is having issues with its servers.

Shouldn't Jesse handle it?

Not really. The problem is, handle it how? When this error is received we don't receive useful information about the cause of the error like a typical 400 error (which means the inputs are the cause of the error).

So we can't really do anything about it but to stop the current session. Or if it's for a non-critical endpoint, simply ignore it.