Bookmarks in PDFs

I open "123.pdf" on Machine A in Adobe Acrobat. When I click on the bookmarks, the bookmarks show up. But when I open the same file "123.pdf" on Machine B in Adobe Acrobat, when I click on the bookmarks, the bookmarks DO NOT appear. What is wrong with the Adobe Acrobat in Machine B? How do I fix it?

Thanks,
Brian