Can’t add application with apt install on container

For whatever reason, in a lxc container in proxmox I can’t find any applications via:

“apt search anything”. Anything is ANY application I try.

Here’s the output:

root@ffmpeg ~# apt install ffmpeg
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
E: Unable to locate package ffmpeg
root@ffmpeg ~#

Yet, at the console at the top node (proxmox) I can find it. That is, “apt install ffmpeg” comes back with a list.
ffmpeg is JUST an example.

What gives?

Russ