Welcome to the forums.
First up, please use code-tags when posting code and not plain-text. You can also edit your post.
So like any problem you need to break it down into steps so when reporting issues, you should also say what you’ve tried to narrow down the problem. If that’s nothing at all then that’s the first problem in itself.
You need to determine if the “OnCollisionEnter2D” is being called. You can attached the debugger to your project and step through what’s being executed. At some point you’ll have to do this so you should learn this ASAP. Alternately you can place “Debug.Log()” calls in there to see if it’s called (you’ll get output to the console).
You can then check what the “gameObject.name” are by outputting that to the console too. When you’ve confirmed it’s actually getting to your “StartCoroutine” then you can start debugging that.