Web application starts with wrong page

I'm coding a web application in java with Intellij Idea. The application starts opening the web browser and showing the index.html page automatically. Since yesterday if I edit the index.html page and then I build and run the application, the web browser show me an old version of the index.html page, as the ide doesn't incorporate the edit made. So I really can't understand how it's possible, and I don't know where I can search in the project file/configuration to fix it. Anyone has some ideas to fix the problem? Thank you!