A stack overflow error during an HTTP request caused the HTTP connection manager to shut down, preventing any further HTTP request to be served. This is the default behavior of the implementation we are using.
We first restarted our server to make it up and running again. Unfortunately, since the issue happened at midnight in our time zone, the server was down for roughly nine hours.
We then fixed the cause of the stack overflow error, which was due to a very uncommon and unexpected edge case not covered by our implementation.
We also made sure that if a stack overflow error ever happened again, it would not shut down the HTTP connection manager, thus having no impact on other requests.