If you’re in digital ocean, I’d recommend to install a clean 18.04 and start over. Then restore your backup to the new server. 14. 04 if close to end of life anyway.
If you don’t have a backup then you can rsync the discourse directory to the new server and then rebuild. I suspect that digital ocean has a page about rsync.
If it’s an emergency that you want to throw money at, I’ll fix it for $300 Redirecting…