Handle service tasks' failures

Hello guys!

In my Camunda process I have a service task that implemented through a backend external task handler.
In this handler I call another service from which I wait to get a unique number.

What happens if the third service is (for any reason) unavailable?
What is the best way to handle this?

Until now, I returned a BpmnErrorResult (which I also added as an error boundary event in the process), but when I tested with an unavailable service I got huge amount of logs in Camunda db.
How to avoid this?

So basically, I am asking (a) what is the best way to handle such issues and (b) how to avoid the excessive logging?

Thank you!!