This is how to fix this simple error.
1. Click on the number after the word Line.
2. It will highlight to you exactly where is the problem as shown below:
3. By clicking on the number, it will indicate to you where is the error.
4. As for my case, my error is found in this code:
5. I need to remove or delete an extra </div> as shown below:
6 . If it is WordPress theme, click the blue Update File button. If it is a Blogger template, click the orange Save template button.
That's all you need to do.