I've been watching non-technical founders debug with AI for months. The same 5 errors come up over and over:

1. "Module not found"

You imported something that doesn't exist or is mistyped. Fix: check spelling, run npm install, verify the package name in package.json.

2. "Cannot read properties of undefined"

You're trying to access a property on something that doesn't exist yet. Fix: add a null check or default value. Usually a timing/async issue.

3. "CORS error"

Your frontend is calling a backend on a different domain without proper headers. Fix: add CORS headers to your API, or use a proxy in development.

4. "TypeError: X is not a function"

You're calling something like a function but it's actually an object, string, or undefined. Fix: console.log the variable right before the call. You probably imported the wrong export.

5. "Unhandled Promise Rejection"

An async function failed silently and nobody caught it. Fix: wrap your await calls in try/catch blocks. Always.

These 5 errors account for probably 90% of the "I'm stuck" moments in vibe coding. Knowing how to instantly recognize and fix them will save you hours every week.

I built a toolkit that explains errors like these in plain English and gives you the actual fix — no Googling, no Stack Overflow rabbit holes. If you're building with AI and want to stop losing hours to debugging, check it out.