I have uploaded a Phaser game that is working fine on my local computer, but it is not working completely on itch.io. Whenever I am trying to change from one state to the other, it shows a blank screen.

Does anyone know the solution for this? Please help.

Open up your browser console and look for errors, it should point you in the right direction.

Check this guide here for some common issues people run into when publishing their game: https://itch.io/docs/creators/html5#common-pitfalls