no longer able to collaborate in Pages between MacBook and iPad pro

I have been working on a pages document for a few days and have collaborated it with my wife, who wrote much of the text. Since Monday this week I have not been able to continue collaborating as I'm prompted that I need to do so using iCloud or on a newer Mac. When I try iCloud I'm told the document is waiting to sync, but nothing is happening. What's going on?

Using 12.7 Monterey, wife using iPad pro