Because my friend likes to never touch his NAS, he had been sitting on OMV1 for the past few years and came to me for help when certain packages no longer worked. I now have him on OMV3, when I attempt to run an update.. I am greeted with this. Any help would be fantastic. Thank you!
Code
W: GPG error https://openmediavault.github.io erasmus InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7E7A6C592EF35D13
W: GPG error https://packages.openmediavault.org erasmus InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7E7A6C592EF35D13
Edit: Fixed by running sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 7E7A6C592EF35D13