Q: Why can't I open a pages document from the cloud?

Hi Li-Ham,

I see that you are having some difficulties with iCloud Drive files. I have some troubleshooting steps that I would like to suggest for you to address this issue properly:

What if my files don't update to iCloud? 

Check these things first:

• Make sure that you have an active Internet connection on your Mac and on your iOS device.
• Sign in to iCloud on all of your devices, and turn on iCloud Drive.
• Install the latest versions of Pages, Numbers, and Keynote. See which versions of Pages, Numbers, and Keynote you can use with iCloud Drive.
• Make sure that you have enough iCloud storage. If you exceed your limit, you can upgrade your iCloud storage.
• Create a new document and save it to see if it uploads to iCloud. If it does, see if the other documents start uploading.

If you tried these steps and your files still don’t upload to iCloud:

1. Stay signed in to iCloud.
2. Save your updated files to a different folder on your Mac or PC.
3. Contact Apple Support.

Get help using iCloud Drive - Apple Support

https://support.apple.com/en-us/HT203052

Keep in mind that these steps may be meant for a different issue than what you are seeing, but are still relevant to your issue, as well. Thanks for using the Apple Support Communities!

Hey again Li-Ham,

I would like for you to confirm that you are able to access your files on iCloud.com. After that, you may wish to try downloading the file to your computer from iCloud.com, then see if you can open the file from your computer that way. Lastly, you may need to reinstall Pages completely:

OS X El Capitan: Reinstall apps that came with your Mac

https://support.apple.com/kb/PH21972

Thanks for coming to the Apple Support Communities!