Explain a stack trace to a junior dev

Here is a stack trace. Explain it to someone in their first year of writing code.

Start by telling me which end to read from and why.

Then walk through it in this order:
1. The one line that actually caused the failure, and why.
2. Which frames are my code and which are library internals.
3. The two most likely root causes, most likely first.
4. What to check or print next.

Do not paste the trace back to me. Do not suggest a fix until you have named the cause.