@BeAware
When I go to the website I get a 502, bad gateway. This means your webserver (nginx) is fine. But the application server (sharkey) is not.
I'm guessing Sharkey didn't come up properly, or at all.
Sharkey is a fork of Firefish? When I had Firefish, to start it after a reboot, I had to do this command:
pm2 start "NODE_ENV=production pnpm run start" --name Firefish
So, maybe the same for you, but the name might be Sharkey?
Then I ran, one time, after it came up, to make this automatic when rebooting:
pm2 save
pm2 startup
I have no idea if this is relevant. Just tossing it out.