I have uploaded all my old iPhone photos to Synology Photos mobile app and they have been available to me to view for a couple of months. Earlier today I was able to view photos in my phone app but later today when I went back in it said “error” and that the content does not exist. It reverted me back to the home folders page and every single one of my folders is gone! I do have it backed up but I am frustrated and confused how on earth this happened?
I understand your frustration and confusion, but something happened without you knowing it.
Maybe you could consider enabling the recycle bin for the homes shared folder in Control Panel.
It’s good that you do have a backup. This is one of the reasons we need backups.