Changes aren't being applied to form

Hi, I've made some changes to my form and saved it but the changes aren't applied (both in the preview window, the actual form or revision history)

What's causing this?  

Apologies for the inconvenience. We have just received news from our back-end team that this is now fixed. Our servers in EU was not able to handle the traffic, which causes this problem. But they have been upgraded to a higher models for optimum performance. Everything should be back to normal now.