Unable to Install macOS, Fresh Download (application is damaged)

[Injury]

Okay, so I just got a fresh download from the app store of macOS Sierra. I created the installer through Terminal which was successful. Upon rebooting into the installer, and selecting "Install macOS" in the macOS Utilities window, I get the message "This copy of the Install macOS Sierra application is damaged, and can't be used to install macOS. "

This is the third time downloading it too. Two through the app store, the third through directly from the website. My connection has been great. My Mac has just been sitting here next to my router with no hiccups. It doesn't make sense why this is occurring.

Can anyone PLEASE help me out? Can anyone provide a different download link or something? It's flat out NOT working.

 

[Injury]

Is there any way to get the installer started through Terminal command in the bootable USB installer media?

 

[Injury]

Figured it out. You have to manually set the time back to 2017 under System Preferences > Date & Time (or through Terminal). The file isn't even damaged. It's an issue with Apple and them not updating the security certificate for some reason.

Once the time is set to 2017, reboot into the installer, turn off WiFi and you should be good to go from there. macOS will automatically set the time back correctly during and after installation, so you won't need to worry about setting it back manually.