iCloud Numbers spreadsheet stuck on loading

I have one particular iCloud Numbers spreadsheet that's been stuck on loading this afternoon, despite being fine this morning. I use it on Google Chrome and have made sure my browser is up to date. I've cleared cookies/cache and signed out and back in. It works fine on my phone and another spreadsheet is also working fine. When I click on another tab and then go back to the spreadsheet, it says "Numbers went offline", even though my internet hasn't experienced any problems. How do I fix this?