On-callMediumoc-p099

Subject Incident responseLevel Senior~20 minCommon in Reliability & on-call interviewsIndustries Technology, Software development

Question

You added a call to a new internal dependency, and it's failing with TLS/certificate errors in production (but worked in testing). How do you diagnose?

What a strong answer looks like

Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.

Learn the concepts

Diagram & narrate the incident

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Run or narrate your approach, then ask the coach.