Socket disconnected before secure TLS connection was established

TL;DR; When deploying NextJS to Vercel, write code ahead of time knowing it’s going to run on AWS Lambdas and make sure you’re giving your server-side code time to execute.


I’ve been building with NextJS for a while now and it’s great for web applications. The server-side functionality1 that NextJS offers is great for compact applications (and very large ones I keep being told), providing the execution model works in your favour.

My wife runs a beauty salon and has numerous web application needs, including things like SMS reminders and a client record system. It would be rude not to build stuff for her and this month (October 2022), I created a small subscription management web application for her customers to be GDPR happy.


Client network socket disconnected before secure TLS connection was established

In development, a server side API call returned early, resulting in this error. Despite it being bad on my part, it was also a great case of Sod’s Law2, because it worked fine in development!

Because the back-end happens to be deployed on Lambdas, I had a gut feeling I knew what was going wrong when I saw the error. The Lambda function will not execute properly if you return early and the dreaded error will absolutely be seen. Ensure that your server call is async and you are resolving promises correctly. Problem solved and panic over. I wonder how many open issues are because of logic around the Lambdas and not allowing them time to execute, despite the app working on the developer machine!

Additional Material

  1. If you have lots of async business logic buried in REST APIs on servers, NextJS doesn’t exclude you from accessing those APIs through the client-side logic or server-side. Client side works as per expectations, even with the normal client side auth systems. You have many choices for your use case! ↩︎

  2. It’s the British cultural axiom of Murphy’s Law↩︎

  • Tags: go, lambda, aws lambda, serverless
  • Categories: aws lambda, lambda, go, serverless