Objects not showing in web peview

I added a new page, XDP365 latest upgrade, but when I check it out in web preview, most of the items which display in page and layer view do not display in web preview. Only one page, but I have wasted two days trying everything I can think of. Hope someone can help, thank you.

You might have two issues here: 1) You may have placed items on the MouseOver layer. Items on that layer become invisible. 2) You must have clicked the button 'Preview current web page' instead of 'Preview whole website'. Go to File/Preview website.