Pages document won't open on iphone

I’m unable to open Pages documents on my iPhone that are saved in my files when I don’t have my iPad with me. I’m guessing this may be something to do with them being saved in iCloud. I just see an error message underneath the file name when I try to download it.

Does anyone have any idea why this happens? Is there a setting I need to change? I don’t always have both my iPhone and iPad with me of course.

I’ve attached a screenshot to show what happens. I tried to open the first document (named blank) and you can see the error message under it. It happens with all documents, not just unnamed ones.

Thanks in advance!