Oh man, you are not the only one! I’m seeing that exact same error on my apps, too.
It looks like AppSheet is having a huge platform problem right now. Everyones seeing the same weird message about appsheet-compute@appsheet-prod.iam.gserviceaccount.com and a “Permission ‘storage.objects.get’ denied” error when they try to save an image or sync a row. It’s totally stopping the apps from working, especially on mobile.
Someone mentioned that the app seems to be working fine on a web browser, though. So if you can, try using that as a workarond for a bit!
Since it’s their service account having the permission error, we just have to wait for the AppSheet team to fix things on thier end. Hopefully they sort it out soon. Ugh!