I've got a Pi3 with OMV4 on it sharing out some samba shares to my network that I use to take backups on. Just built it a few days ago, and it's been running fine, no issues. Today I got on it to just make a little script to alert me if my backups failed. Which involved installing msmtp. That's pretty much all I did. Now I can't get to the webgui, and it gives me a 403 Forbidden error. I tried running omv-firstaid, but get command not found (running as root). When I tail the openmediavault-webui_error.log, it shows a bunch of the following error:

*1 directory index of "/var/www/openmediavault/" is forbidden, client: ::ffff:127.0.0.1, server: openmediavault-webgui, request: "GET / HTTP/1.1", host: "127.0.0.1"

Anyone know what the heck might have happened? I've run apt update and apt upgrade, and rebooted, but to no avail. I can't seem to get the web gui to load.